o 
LO 

o 


Univ.  ( f  C-.^H 


NOSTRANFHCIENCE  SERIES. 

i.  ./.—WATER  AND  WATER  SUPPLY,  By 
PROF.  W.  H.  CORFIELD,  M.  A.,  of  the 
University  College,  London. 

No.  18.— SEWERAGE  AND  SEWAGE  UTILI- 
ZATION. By  PROF.  W.  H.  CORFIELD, 
M.  A.,  of  the  University  College,  Lon- 
don. 

No,  19.— STRENGTH  OF  BEAMS  UNDER 
•  TRANSVERSE  LOADS.  By  PROF. 
W.  ALLEN,  Author  of  "  Theory  of 
Arches."  With  Illustrations. 

»  20. —BRIDGE  AND  TUNNEL  CENTRES. 
By  JOHN  B.  MCMASTKRS,  (1.  E.  With 
Illustrations. 

Xo. -21.— SAFETY  VALVES.  By  RICHARD  H. 
BUKL,  0.  E.  With  Illustrations. 

No.  22.— HIGH  MASONRY  DAMS.     By  JOHN  B. 

MCMASTERS,  C.  E.     With  Illustrations. 
\o.  o;>._ THE  FATIGUE  OF  METALS  UNDER 

REPEATED  STRAINS,  with   various 

I  Tables  of  Results  of  Experiments.  From 

the  German  of  PROF.  LUDWIG  SPANGEN- 
BERG.  With  a  Preface  by  S.  H.  SHREVE, 
A.  M.  With  Illustrations. 
24 .__ A  PRACTICAL  TREATISE  ON  THE 
TEETH  OF  WHEELS,  with  the  Theo- 
ry of  the  Use  of  Robinson's  Odonto- 
"•raph.  By  S.  W.  ROBINSON,  Prof,  of 
Mechauieal  Engineering.  Illinois  In- 
dustrial University. 

No.  25.— THEORY  AND  CALCULATIONS  OF 
CONTINUOUS  BRIDGES.  By  MANS- 
FIELD  MERRIMAN,  C.  E.  AVith  Illustra- 
tions. 

No.  26.— PRACTICAL  TREATISE  ON  THE 
PROPERTIES  OF  CONTINUOUS 
BRIDGES.  By  CHARLES  BENDER,  C.  E . 

No.  27.— ON  BOILER  INCRUSTATION  AND 
CORROSION.  By  F.  J.  ROWAN. 


Gninr  OIP 


THE  PRESERYATIOH 

OF 

TIMBER 


BY  THE  USE  OF 


SAMUEL  BAGSTER  BOULTON, 

ASSOC.  INST.  C.  E. 


REPRINTED   FROM   VAN   NOSTRAND'S   MAGAZINE. 


NEW  YOKE: 

I).   VAN  NOSTRAND,   PUBLISHER, 
2B  MURRAY  AND  27  WARREN  STREETS. 


JOHN  S.  PRELL 

Civil  &  Mechanical  Engineer. 


GIFT 


1372- 


PREFACE. 


The  preservation  of  wooden  structures 
from  decay,  or  from  the  ravages  of  in- 
sects, is  a  subject  of  unfailing  interest  to- 
engineers. 

The  fact  that  this  paper  was  prepared 
for  the  Institution  of  Civil  Engineers, 
and  was  discussed  by  prominent  mem- 
bers, is  a  sufficient  guaranty  that  it  pre- 
sents the  facts  that  are  best  worth  know- 
ing now  in  the  possession  of  practical 
men. 

Some  chemical  tables,  appended  es- 
says, and  a  long  bibliographical  list  are 
omitted  in  this  reprint. 


M7S6010 


S.  PRELL 

Civil  &  Mechanical  Engineer. 

SAN  FilAK  CISCO,  CAL. 

THE 

ANTISEPTIC  TREATMENT  OF  TIMBER. 


IN  January,  1853,  a  paper  upon  Timber 
Preserving  was  contributed  to  this  Insti- 
tution* by  the  author's  partner,  the  late 
Mr.  Henry  Potter  Burt,  Assoc.  Inst. 
C.  E.  Since  that  date,  the  use  of  Anti- 
septics for  the  treatment  of  timber  has 
largely  increased,  and  is  year  by  year  in- 
creasing. For  engineering  purposes,  the 
process  called  creosoting,  which  consists 
in  the  injection  of  the  coal-tar  oils,  has 
in  this  kingdom  entirely,  and  in  other 
countries  to  a  very  considerable  extent,, 
displaced  the  other  well-known  meth- 
ods. 

Concurrently  with  this  development^  a 
series  of  remarkable  discoveries  in 
chemical  science  has  raised  the  manufac- 
tures connected  with  the  residual  prod- 

*  Institution  of  Civil  Engineers. 


nets  of  gas-making  to  a  position  of  great 
and  growing  importance. 

It  is  proposed  in  the  present  paper, 
to  give  a  short  account  of  the  history 
and  development  of  the  use  of  antiseptics 
for  preventing  the  decay  of  timber.  A 
reference  to  the  processes  employed  in 
coal-tar  distillation  will  be  pertinent  to 
the  subject,  in  so  far  as  it  will  indicate 
-what  are  and  have  been  the  usual  con- 
stituents of  the  tar  oils  used  for  inject- 
ing wood.  The  author  proposes  to  add 
some  results  derived  from  his  thirty- four 
jears'  experience  in  connection  with  this 
group  of  manufactures,  together  with  the 
•outcome  of  some  research,  and  of  a  num- 
ber of  experiments  specially  undertaken 
Tvith  a  view  to  the  elucidation  of  ques- 
iions  referred  to  in  the  paper. 

EARLY  HISTORY  OF  TIMBER    PRESERVING. 

Timber  was  naturally  the  first  ma- 
terial employed  by  man  for  the  purposes 
of  constructive  engineering.  If  it  be 
true  that  the  first  models  of  Grecian 
architecture  were  copied  from,  and  re- 


tained  some  of  the  distinctive  features 
of,  buildings  in  wood,  then  may  still  be 
seen  accorded,  upon  the  columns  of  the 
five  great  orders  of  architecture,  proofs 
that  the  Greeks  or  their  precursors  took 
special  expedients  to  preserve  timber 
from  decay.  The  wooden  pillar  was 
placed  upon  a  block  of  stone  to  pre- 
serve it  from  the  humidity  of  the  soil, 
and  it  was  covered  at  the  top  by  a  slab 
or  tile  to  throw  off  the  rain.  These 
contrivances  are  supposed  to  have  been 
copied  in  the  base  and  capital  of  the 
column,  when  wood  came  to  be  replaced 
by  stone.  Scamozzi  imagines  also,  that 
the  mouldings  represent  metal  hoops, 
placed  around  the  wooden  pillars  to  pre- 
vent them  from  splitting. 

Allusions  to  various  substances  em- 
ployed for  preserving  timber  and  other 
vegetable  fibers  from  decay,  are  frequent 
in  the  writings  of  the  ancients.  Tar  and 
pitch  were  used  for  painting  or  smearing 
wood  from  periods  of  the  most  remote 
antiquity.  Greek  and  Roman  authors 
narrate,  that  the  astringent  portions  of 


8 

the  oil  expressed  from  olives  (Amurca 
16),  also  oils  derived  from  the  Cedar, 
the  Larch,  the  Juniper  and  the  Nard- 
Bush  (Valeriana)  were  used  for  the  pres- 
ervation of  articles  of  value  from  decay, 
or  from  the  attacks  of  insects.  The 
magnificent  statue  of  Zeus  by  Phidias 
was  erected  in  a  grove  at  Olympus  where 
the  atmosphere  was  damp ;  the  wooden 
platform  upon  which  it  stood  was  there- 
fore imbued  with  oil.  The  famous  statue 
of  Diana  at  Ephesus  was  of  wood.  If 
its  origin  was  believed  to  be  miraculous, 
no  standing  miracle  was  relied  on  for  its 
preservation.  Pliny  asserts  upon  the 
authority  of  an  eye-witness,  Mucianus, 
that  it  was  kept  saturated  with  oil  of 
Nard  by  means  of  a  number  of  small 
orifices  bored  in  the  woodwork.  The 
same  author  remarks  that  wood  well 
rubbed  with  oil  of  Cedar,  is  proof  aginst 
wood-worm  and  decay.  The  art  of  ex- 
tracting and  preparing  oils,  resins,  tar 
and  pitch  from  various  trees  and  plants, 
and  from  mineral  deposits,  is  mentioned 
by  Herodotus,  and  at  great  length  by 


Pliny.  This  last  author  describes  in  de- 
tail, the  manufacture  of  no  less  than 
fort^eight  different  kinds  of  oils.  Of 
the  employment  of  the  oxides  or  salts  of 
metals  by  the  ancients,  for  wood  preserv- 
ing, there  is  no  direct  evidence. 

EGYPTIAN  MUMMIES. 

Of  all  the  methods  employed  by  man- 
kind for  the  artificial  preservation  of  or- 
ganized substances,  there  are  perhaps 
none  which  have  equaled  in  success  the 
processes  of  the  ancient  Egyptians.  The 
durable  results  of  these  processes  are 
amazing,  and  although  the  topic  is  a 
hackneyed  one,  it  is  nevertheless  insep- 
arably connected  with  the  subject  of  this 
paper.  The  descriptions  by  co-temporary 
writers  of  the  Egyptian  art  of  embalming 
the  dead  are  somewhat  conflicting ; 
moreover,  they  do  not  adequately  explain 
the  appearances  presented  by  many  of 
the  mummies  themselves.  The  bodies 
are  said  to  have  been  imbued,  either  with 
resinous  or  odoriferous  gums,  or  more 
frequently  with  bitumen  or  with  oil 


10 


of  cedar,  or  commonly  with  natrum, 
and  often  with  several  of  these  sub- 
stances in  succession.  So  far,  these 
statements  are  confirmed  by  modern 
investigation.  By  reading  Herodotus 
and  Diodorus  Siculus,  however,  it 
would  perhaps  seem  that  the  body 
was  first  steeped  in  the  natrum  for 
seventy  days,  and  then  subjected  to  the 
oily  or  bituminous  preparation.  In  other 
places  it  might  be  gathered  that  the  oily 
preparation  came  first,  and  the  steeping 
in  natrum  afterwards.  Without  further 
explanation,  neither  of  these  processes 
would  appear  to  be  practicable.  At 
ordinary  temperatures,  the  steeping  in 
the  one  preparation  would  interfere  with 
the  absorption  of  the  other.  Natrum  is 
supposed  to  have  been  a  natural  sub- 
stance, obtained  from  some  briny  lakes, 
still  existing  in  the  neighborhood  of 
Cairo,  and  consisting  principally  of  a 
mixture  of  sodium-sesqui- carbonate,  so- 
dium-chloride and  sodium-sulphate.  Rou- 
yer,  who  accompanied  the  army  of  Napo- 
leon to  Egypt  in  1798,  expressed  his 


11 

conviction  that  the  mummies  had  been 
placed  in  ovens  in  order  to  eliminate 
moisture,  and  to  facilitate  the  penetra- 
tion of  the  bitumen.  But  no  ancient  au- 
thor mentions  any  such  process,  nor  is 
there  any  record  of  it  amongst  the 
numerous  and  detailed  pictorial  repre- 
sentations which  have  been  discovered  in 
tombs  and  temples. 

Pettigrew,  in  his  valuable  work  on 
this  subject,  whilst  giving  the  results  of 
his  examination  of  various  mummies,  and 
of  analyses  of  embalming  materials,  ex- 
presses his  opinion  that  the  bodies  must 
have  been  subjected  to  a  very  consider- 
able degree  of  heat,  as  even  the  inmost 
structure  of  the  bones  is  penetrated  by 
the  antiseptics.  By  some  it  has  been 
supposed  that  this  was  effected  by  steep- 
ing the  body  in  a  cauldron  of  heated 
bitumen.  Pettigrew's  most  striking  ex- 
periment was  made  with  the  heart  of 
a  mummy,  from  which  he  succeeded  in 
withdrawing  by  maceration  the  preserva- 
tive substanceR,  when,  after  3,000  years  of 
perfect  preservation,  the  heart  began  at 


12 

once  to  putrefy.  This  is  a  striking  proof, 
both    of  the   efficacy   of  the   substances 
employed,  and  also  of  the  fact,  that  the 
immunity  from  decay  was  not  due  to  a 
chemical   transformation  produced  once 
for  all,  but  that  it  depended   upon  the 
abiding  presence   of  the  antiseptic.     In 
recent  anatomical  practice,  carbolic  acid 
has  been  used  for  injecting  bodies  for 
purposes   of    dissection.      When  this  is 
done,  however,  it  is  found  necessary  to 
renew  the  process  after  the  lapse  of  a  few 
weeks,  a  contrast  to  the  antiseptics  em- 
ployed  by  the   Egyptians.     Pettigrew's 
description  showed  that  the  worst  pre- 
served of  the  mummies  are  those   pre- 
pared with  natrum  alone,  the  most  per- 
fect being  those  in  which  solid  resins  or 
bitumens  remain  incorporated.     Natrum 
is  frequently  found   accompanying    the 
bitumen  in  some  of  the  most  successfully 
preserved  specimens.    It  is  probable  that 
some  astringent  or  other  substances  were 
also    used,    the    secret    of    which    has 
hitherto  eluded  modern  investigation. 
The  author  has  caused   some   experi- 


13 


ments  to  be  made  with  pieces  of  timber, 
in  order  to  test  a  theory  which  suggested 
itself  to  his  mind.  The  wood  was  first 
thoroughly  impregnated  with  a  mixed 
solution  of  the  three  salts  of  sodium  of 
which  the  natrum  brine  is  composed 
Afterwards  the  wood  was  steeped  in  tar 
oil,  heated  to  230°  Fahrenheit.  The  heat 
of  the  tar  oil  volatilized  the  water  of  the 
soda  solution,  and  the  oil  took  the  place 
of  the  water.  The  timber  remained  im- 
pregnated with  the  saline  particles,  and 
saturated  with  the  tar  oil.  May  not  this 
have  been  the  method  used  by  the  Egyp- 
tians to  impregnate  both  with  natrum 
and  oils  ? 

There  is  no  doubt  that  the  ancients 
had,  by  observation  and  experience,  ac- 
quired considerable  practical  knowledge 
of  antiseptic  substances.  They  were 
also  of  opinion  that  those  woods  lasted 
the  longest  which  were  most  odoriferous, 
or,  in  other  words,  those  which  contained 
the  greatest  quantity  of  resin.  They 
knew  that  timber  continually  kept  under 
water  was  less  liable  to  decay  than  when 


14 


exposed  to  the  atmosphere.  They  ob- 
served the  ravages  of  the  Teredo  navalis 
upon  timber  placed  in  the  sea.  But  it  is 
useless  to  seek  amongst  the  writings  of 
the  elder  Classics  for  any  reasonable  the- 
ory in  explanation  of  these  phenomena. 

Growth  of  theories  upon  the  causes  of 
Putrefaction. — It  is  not  until  the  eight- 
eenth century  of  the  present  era  that 
anything  beyond  the  merest  trace  can  be 
detected  of  serious  analytical  research 
into  the  causes  of  decomposition.  After 
the  fanciful  dreams  of  the  alchemists 
had  been  dissipated,  the  more  solid  por- 
tion of  their  labors,  facts  arrived  at  in 
the  course  of  their  experiments,  remained 
for  the  uses  of  science.  Investigations 
were  undertaken  respecting  the  phe- 
nomena of  fermentation  and  of  putrefac- 
tion, animal  and  vegetable.  It  was  at 
one  time  declared  that  putrefaction  was 
due  to  the  escape  of  an  element  called 
phlogiston,  an  imaginary  substance  which 
was  believed  in  by  such  eminent  chem- 
ists as  Scheele,  the  discoverer  of  chlor- 
ine, and  Dr.  Priestley,  the  discoverer  of 


15 


oxygen.  Later  on  Dr.  Macbrlde  pro- 
pounded a  theory  that  carbonic  acid  gas 
had  a  special  power  of  promoting  cohe- 
sion, and  that  putrefaction  was  due  to 
its  being  given  off.  None  of  these  the- 
ories explained  why  putrefaction  did  not 
attack  the  tissues  until  after  the  vital 
movement  had  ceased.  By  the  com- 
mencement of  the  present  century,  how- 
ever, it  began  to  be  generally  believed 
that  the  putrefaction,  at  least  of  vege- 
table matter,  was  a  species  of  fermenta- 
tion, although  it  was  not  admitted  that 
ferments  of  any  kind  were  the  products 
of  living  organisms.  Little  by  little  the 
similarity  of  the  natural  processes  con- 
nected with  the  fermentation  of  aliment- 
ary substances,  the  decay  of  vegetable 
tissues,  and  the  putrefaction  of  the 
bodies  of  animals  began  to  be  recog- 
nized ;  and,  to  the  great  advantage  of 
scientific  progress,  these  three  classes  of 
phenomena  have  ever  since  been  studied 
in  close  connection  with  each  other. 

In  the  meantime  practice  stole  a  march 
upon  theory.     About  the  year  1770  Sir 


16 


John  Pringle  published  a  list  of  anti- 
septics, in  which  example  he  was  folio  wed 
by  Dr.  Macbride.  Many  of  the  substances 
proposed  by  these  and  other  theorists, 
particularly  the  alkaline  bodies,  are  abso- 
lutely injurious  to  timber.  But  towards 
the  close  of  the  last  century  and  at  the 
beginning  of  the  present,  experiment 
was  greatly  stimulated  by  the  wants  of 
the  British  navy.  During  the  colossal 
struggles  of  Great  Britain  with  hosts  of 
adversaries,  the  very  existence  of  the 
nation  appeared  to  be  staked  upon 
her  fleets.  The  great  prevalence  of  dry- 
rot  in  the  timbers  of  British  men-of- 
war  assumed  the  proportions  of  a  na- 
tional calamity.  It  was  said  that  a  single 
70-gun  ship  required  for  its  construction 
the  oak  of  40  acres  of  forest,  and  that 
the  supply  would  fail.  It  was  in  1812 
that  Lukin  tried,  in  the  Woolwich 
Dockyard,  his  disastrous  experiment 
with  the  injection  of  resinous  vapors. 
More  practical  suggestions  were  soon 
forthcoming,  and  the  use  of  the  salts  of 
various  metals  began  to  be  recommend- 


17 


ed.  Sir  Humphrey  Davy  suggested  cor- 
rosive sublimate ;  Thomas  Wade  (in 
1815),  the  salts  of  copper,  iron,  and 
zinc.  The  opinion  gained  ground  that 
poisons  of  various  kinds  were  cor- 
rectives to  the  decay  of  timber. 

From  the  year  1768  up  to  the  pres- 
ent time,  the  records  of  the  Patent 
Office  contain  lists  of  almost  every 
conceivable  antiseptic,  suitable  or  un- 
suitable, for  the  preservation  of  wood. 

Progress  during  the  Railway  Era. — 
But  it  is  since  the  birth  and  growth  of 
the  railway  system  that  the  antiseptic 
treatment  of  timber  may  be  said  to  have 
received  its  most  important  development. 
The  stone  blocks  and  other  solid  sup- 
ports, at  first  used  for  the  permanent  way 
of  railways,  were  found  to  be  too  rigid, 
and  had  to  be  replaced  by  a  more  elastic 
material.  The  wooden  sleepers  which 
were  substituted  decayed  so  rapidly  that 
some  artificial  method  for  prolonging 
their  duration  began  to  be  considered  as 
an  engineering  necessity.  By  the  year 
1838,  four  several  systems  of  antiseptic 


18 


treatment  werej  fairly  before  the  public, 
and  competingjfor  the  favor  of  engineers. 
These  were :  Corrosive  sublimate,  intro- 
duced by  Mr.  J.  H.  Kyan ;  sulphate  of 
copper,  by  Mr.  J.  J.  Lloyd  Margary ; 
chloride  of  zinc,  by  Sir  William  Burnett ; 
heavy  oil  of  tar  (afterwards  called  creo- 
sote), by  Mr.  John  Bethell. 

Corrosive  Sublimate,  or  bichloride  of 
mercury,  was  successfully  used  by  Hom- 
berg,  a  French  savant,  in  1705,  for  pre- 
serving wood  from  insects.  It  was  rec- 
ommended by  De  Boissieu  in  1767.  In 
1730  the  Dutch  Government  tried  it  upon 
wood  immersed  in  sea  water  as  a  remedy 
against  the  Teredo  navalis,  but  for  this 
purpose  it  failed.  In  the  "  Encyclopae- 
dia Britannica,"  in  1824,  it  is  recorded 
that  Sir  Humphrey  Davy  recommends  its- 
use  for  timber.  Ryan's  first  patent,  for 
the  employment  of  corrosive  sublimate 
for  wood-preserving  was  taken  out  in 
1832.  His  first  success  was  gained  by 
the  preservation  of  the  woodwork  of  the 
Duke  of  Devonshire's  conservatories. 
Kyanizing  was  for  a  long  time  by  far  the 


19 


most  popular  of  the  timber  preserving 
processes  in  this  country,  and  the  name 
is  to  this  day  frequently  applied  erron- 
eously to  other  systems.  Used  in  sea- 
water,  however,  by  the  British  Admiralty, 
this  process  turned  out  a  failure,  as  it 
had  done  under  similar  circumstances 
with  the  Dutch  government  a  century 
earlier.  Kyanizing  has  met  with  a  con- 
siderable amount  of  success  in  compara- 
tively dry  situations ;  but  in  water,  and 
particularly  in  sea-water,  it  appears  to 
have  invariably  failed,  as  have  all  the 
salts  of  metals.  Corrosive  sublimate  is 
somewhat  volatile  at  ordinary  tempera- 
tures ;  it  also  has  the  drawback  of  pro- 
ducing injurious  effects  upon  the  work- 
men employed  in  handling  it. 

Sulphate  of  copper. — The  use  of  this 
and  of  other  salts  of  copper  was  recom- 
mended by  De  Boissieu  and  by  Borden- 
ave  in  1767,  and  by  Thomas  Wade  in 
1815.  In  1837  Mr.  Margary  took  out  a 
patent  for  the  use  of  sulphate  and  asce- 
tate  of  copper.  Sulphate  of  copper  has 
perhaps  been  the  mo&t  successful  of  all 


the  metallic  salts  as  an  antiseptic  for 
timber.  Applied  in  various  ways  it  was 
popular  in  France  long  after  it  had  been 
given  up  in  this  country.  It  is  still  in 
use  in  France,  to  a  limited  extent,  for 
sleepers  and  telegraph  poles. 

Chloride  of  zinc. — This  was  recom- 
mended by  Thomas  Wade  in  1815,  and 
by  Dr.  Boucherie  in  1837  ;  and  a  patent 
for  its  application  was  taken  out  in  this 
country  by  Sir  William  Burnett  in  1838. 
The  process  of  Burnettizing  was  at  one 
time  much  patronized  by  the  British  Ad- 
miralty. For  railway  sleepers  it  was  ex- 
tensively adopted  in  France  by  the  au- 
thor's firm,  principally  on  the  railways 
from  Orleans  to  Bordeaux,  and  from  Caen 
to  Cherbourg.  It  is  no  longer  used  in 
France,  but  it  is  still  employed  in  Hol- 
land and  in  Germany.  Chloride  of  zinc 
is  a  powerful  antiseptic,  but  its  weak 
point  for  wood-preserving  consists  in  its 
extreme  solubility  in  water. 

Heavy  oils  of  Tar,  commonly  called 
Creosote. — As  early  as  1756  attempts 
were  made,  both  in  England  and  Ameri- 


21 


ca,  as  described  by  Knowles,  to  inject  or 
impregnate  timber  with  vegetable  tars  or 
with  extracts  therefrom.     The  first  men- 
tion of  the  products  of  the  distillation  of 
gas- tar,  to  be  used  separately  for  impreg- 
nating timber,  appears   to   be  by  Franz 
Moll.     This  inventor  took  out  a  patent 
in  1836  for  injecting  wood  in  closed  iron 
vessels  with  the  oils  of  coal-tar  first  in  a 
state  of  vapor,  and  next  with  the  heated 
oils  in  the  ordinary  liquid  state.     He  rec- 
ommended the  adoption  both  of  the  oils 
lighter  than  water,  and  of  the  oils  heavier 
than  water,  calling  the  former  "  Eupion," 
and   the   latter   "Kreosot."      He   relied 
upon  the  Kreosot  for  its  antiseptic  quali- 
ties, but  proposed   to   use  the  light  oils 
separately,  at  the  commencement  of  the 
operation,  for  the  purpose  of  facilitating 
the  absorption  of  the   heavy  oil.     This 
plan  has    never   been   acted  upon,  as  it 
would  be  obviously  wasteful  and  unprac- 
tical to  inject  the  lighter   oils,  or  crude 
naphthas,  which  would  immediately  evap- 
orate. 

The  practical  introduction  of  the  proc- 


22 


ess  is  due  to  Mr.  John  Bethell.  His  now 
celebrated  patent,  which  is  dated  July, 
1838,  does  not  mention  the  words  "  Cre- 
osote" or  "  Creosoting."  It  contains  a 
list  of  no  less  than  eighteen  various  sub- 
stances, mixtures  or  solutions,  oleagi- 
nous, bituminous,  and  of  metallic  salts. 
Amongst  them  is  mentioned  a  mixture 
consisting  of  coal-tar  thinned  with  from 
one-third  to  one-half  of  its  quantity  of 
dead  oil  distilled  from  coal-tar.  This  is 
the  origin  of  the  so-called  Creosoting 
process.  Creosote,  correctly  so  called,  is 
the  product  of  the  destructive  distilla- 
tion of  wood,  and  coal-tar  does  not  con- 
tain any  of  the  true  Creosote,  which  has 
never  been  used  for  timber-preserving. 
But  a  substance,  since  called  carbolic 
acid,  or  phenol,  had  been  discovered  in 
coal-tar ;  it  was  thought  by  some  to  be 
identical  with  the  Creosote  of  wood, 
hence  the  process  came  to  be  miscalled, 
after  a  time  the  creosoting  process.  It 
is  in  this  popular  sense  only  that  the 
word  Creosote  is  to  be  understood  in  the 
remainder  of  this  paper.  The  two  sub- 


23 


stances,  Creosote  and  Carbolic  acid,  are 
described  and  contrasted,  and  their  vary- 
ing properties  delineated  in  Dr.  Tidy's 
"Handbook  of  Chemistry." 
*  Competition  of  the  Processes — Theory 
of  Eremacausis. — In  addition  to  the 
four  processes  already  mentioned,  a  pat- 
ent for  a  fifth  was  taken  out  by  Mr. 
Charles  Payne  in  1846.  His  plan  con- 
sisted in  the  injection  into  the  timber, 
first  of  a  solution  of  a  sulphuret  of  barium 
or  calcium,  and  next  of  a  solution  of 
sulphate  of  iron,  the  object  being  to  form 
an  insoluble  sulphuret  in  the  pores  of 
the  wood.  This  process  was  tried  to 
some  extent  both  in  England  and  in 
France,  but  it  was  a  complete  failure,  and 
is  mentioned  only  by  way  of  reference. 

From  ]838  to  1853,  at  which  last  date 
the  paper  of  Mr.  H.  P.  Burt  was  read  at 
this  institution,  the  four  processes,  Kyan- 
izing,  Margaryizing,  Burnettizing  and 
Creosoting  had  been  in  active  competi- 
tion. The  prevailing  theory  at  that  time 
as  to  the  causes  of  the  decay  of  timber 
was  shaped  by  the  opinions  of  the  great 


24 


chemist  Liebig.  Liebig  taught  that  the 
processes  of  fermentation  in  certain  fluids 
and  of  the  putrefaction  or  decay  of  or- 
ganized bodies,  animal  and  vegetable, 
were  caused  by  a  species  of  slow  com-  • 
bustion,  to  which  he  applied  the  term 
eremacausis.  He  held  that  this  decom- 
position could  be  produced  by  contact 
with  portions  of  other  bodies  already  un- 
dergoing eremacausis.  That  it  required 
for  its  ordinary  development  the  pres- 
ence of  moisture  and  of  atmospheric  air; 
that  its  action  was  provoked  by  oxygen, 
and  that  its  method  of  action  was  by  a 
communication  of  motion  from  the  atoms 
of  the  infecting  ferment  to  the  atoms  of 
the  body  infected.  He  denied  that  fer- 
mentation, putrefaction  and  decomposi- 
tion were  caused  by  fungi,  animalcules, 
parasites  or  infusoria,  although  these  or- 
ganisms might  sometimes  be  present 
during  the  processes. 

But  he  also  stated  that  the  phenomena 
of  decomposition  might  be  suspended  by 
extreme  heat  or  cold,  that  they  were  ac- 
celerated by  the  action  of  alkalies,  and 


/ 

25 


retarded  by  that  of  acids,  and  that  they 
might  be  arrested  by  the  use  of  certain 
antiseptics.  If,  however,  the  theory  of 
eremacausis  be  accepted,  and  if  its  phe- 
nomena be  due  entirely  to  a  communica- 
tion of  molecular  motion,  and  not  at  all 
to  the  action  of  living  germs,  does  any 
adequate  explanation  remain  of  the  ef- 
fects produced  by  antiseptics  ?  With  re- 
gard to  timber,  theorists  were  ready 
with  an  answer  to  this  question,  and  they 
deduced  their  theories  from  further 
teachings  of  the  great  German  chemist. 
Liebig,  enlarging  upon  the  views  of  pre- 
vious investigators,  had  proclaimed  the 
identity  in  composition  of  the  animal  and 
vegetable  albumens.  The  blood  of  ani- 
mals and  the  sap  of  plants  are,  during 
life,  the  circulating  media  of  the  vital 
growth ;  after  death  they  are  the  por- 
tions of  the  respective  bodies  which  pu- 
trefy most  rapidly ;  both  are  largely  com- 
posed of  albumen.  The  sap  freshly 
drawn  from  a  tree  will  commence  to  pu- 
trefy within  twenty-four  hours.  It  was 
proclaimed  (although  probably  not  by 


26 


Liebig),  that  the  coagulation  of  the  al- 
bumen was  the  true  specific  against  the 
decay  of  wood.  Corrosive  sublimate, 
sulphate  of  copper,  chloride  of  zinc,  and 
the  tar  oils  were  all  powerful  agents  for 
that  purpose.  It  was  claimed  for  all 
four  of  these  processes  that  they  coagu- 
lated the  albumen  contained  in  the  wood, 
and  that  they  formed  insoluble  compounds 
therein,  thus  arresting  decay. 

Prolonged  experience  has,  however, 
proved  that  the  salts  of  metals  are  not  so 
permanent  in  their  effects  as  the  tar  oils. 
The  discussion  which  took  place  at  this 
institution  in  January,  1853,  upon  the 
occasion  of  the  reading  of  Mr.  Burt's 
paper,  was  an  interesting  one,  and  was 
joined  in  by  most  of  the  leading  engi- 
neers of  the  country.  Whilst  the 
other  processes  were  admitted,  in  many 
instances,  to  have  done  good  service, 
the  Creosoting  process  was  generally 
held,  after  fifteen  years'  experience,  to 
have  proved  the  most  stable  and  reliable. 
In  many  subsequent  discussions,  the  pro- 
longed duration  of  creosoted  timber  had 


27 


been  a  matter  of  constant  and  reiterated 
testimony.  Gradually  the  Creosoting 
process  took  the  place  of  the  others  by 
a  species  of  "survival  of  the  fittest,'' 
until  in  England  it  entirely  extinguished 
its  rivals.  The  author's  last  experience 
of  Kyanizing  in  England  was  carried  out 
in  1863. 

In  France,  the  Creosoting  process  was 
later  in  establishing  itself,  partly  owing 
to  the  difficulty  which  at  one  time  existed 
in  procuring  Creosote  in  that  country, 
partly,  also,  to  the  popularity  of  the  sul- 
phate of  copper  process,  enhanced,  as  it 
was  by  the  ingenuity  of  the  method  em- 
ployed for  its  injection  by  Dr.  Boucherie. 
But  it  was  discovered  even  in  France, 
and  notwithstanding  the  theories  of  in- 
soluble compounds  being  formed  in  the 
timber,  that  the  salts  of  metals  were 
gradually  washed  out  of  the  wood  in 
moist  situations.  In  1861,  the  French 
chemist  Pay  en  reported  that  sulphate  of 
copper  could  be  almost  entirely  removed 
from  wood  by  repeated  washings  with 
water,  and  in  1867  he  reported  that  the 


28 


whole  could  be  so  removed.  This  has 
been  confirmed  by  the  testimony  of  Max- 
ime  Paulet. 

The  experiments  of  Mr.  Forestier,  un- 
dertaken for  the  French  Government, 
and  the  prolonged  and  exhaustive  experi- 
ments of  the  Dutch  Government,  are 
conclusive  as  regards  the  efficiency  of 
creosoting  against  the  ravages  of  the 
Teredo  navalis,  in  cases  where  the  tim- 
ber has  been  efficiently  prepared,  and 
with  a  suitable  kind  of  creosote.  These 
experiments  are  referred  to  in  the  Min- 
utes of  Proceedings  of  this  Institution, 
vol.  xxvii.  The  experiments  undertaken 
by  Mr.  Crepin  on  Tbehalf  of  the  Belgian 
Government,  and  the  independent  testi- 
mony of  many  of  the  leading  engineers 
of  this  country,  have  also  from  time  to 
time  been  brought  to  the  notice  of  this 
Institution,  in  confirmation  of  the  success 
of  the  Creosoting  process  against  the 
ravages  of  marine  insects.  On  the  other 
hand,  there  are  distinct  and  well  authen- 
ticated instances  of  failure.  An  inquiry 


29 

into  the  causes  of  such  failures  is  one  of 
the  main  objects  of  this  paper. 

Origin  and  properties  of  the  Tar  Oils. 
— As  the  tar  oils  gained  in  usefulness, 
their  varying  qualities  became  subjects 
of  increasing  interest.  A  brief  digres- 
sion may  here  be  useful,  in  order  to  show 
the  process  of  manufacture  by  which 
these  tar  oils  are  procured.  It  will  be 
seen  that  from  coal,  as  it  is  carbonized  at 
the  gasworks,  four  well  known  products 
are  obtained,  viz.,  illuminating  gas,  am- 
moniacal  liquor,  coal-tar,  and  coke.  Gas 
liquor,  or  ammoniacal  liquor  forms 
the  basis  of  a  separate  industry ;  the 
ammoniacal  products  are  of  no  utility  for 
timber  preserving.  The  antiseptic  sub- 
stances are  all  obtained  from  the  distilla- 
tion of  coal  tar,  a  black,  viscous  substance 
of  a  consistency  resembling  treacle.  The 
tar  is  subjected  to  the  heat  of  a  furnace 
placed  beneath  the  still,  the  operation  be- 
ing aided  sometimes  by  the  injection  of 
steam,  sometimes  by  the  application 
of  an  exhausting  air  pump.  The  prod- 
ucts of  distillation  come  over  very  nearly 


30 


in  the  order  of  their  respective  volatili- 
ties, those  of  lightest  specific  gravity  be- 
ing followed  in  succession  by  heavier 
and  yet  heavier  ones  as  the  heat  increases. 
The  temperature  during  the  distillation 
ranges  from  180°  to  758°  Fahrenheit. 
This  preliminary  process,  although  now 
carried  out  with  more  skill  and  economy 
than  formerly,  has  not  varied  much  dur- 
ing the  last  fifty  years  in  its  main  object, 
which  is  to  break  up  the  tar  into  three 
groups  of  products,  viz.,  oils  lighter  than 
water  (crude  naphthas) ;  oils  heavier  than 
water,  pitch,  the  residuum  of  distillation, 
which  last  product  is  run  out  from  the 
bottom  of  the  still,  and  solidifies,  upon 
cooling,  into  a  hard,  black  substance.  It 
is  in  connection  with  the  component 
parts  of  the  two  groups  of  oils,  and  their 
separate  and  subsequent  treatment,  that 
some  of  the  best  known  and  most  bril- 
liant discoveries  of  modern  industrial 
chemistry  have  been  developed.  The  oils 
lighter  than  water,  however,  have  no 
part  in  the  preservation  of  timber.  It  is 
not  uncommon  to  hear  inquiries  as  to 


31 


whether  the  discovery  of  the  aniline  dyes 
has  not,  somehow  or  other,  interfered 
with  the  quality  of  the  Creosoting  liquor. 
There  exists  a  singular  and  unfounded 
prejudice  on  this  subject.  The  materials 
for  the  aniline  dyes  are  not,  and  never 
have  been,  taken  from  the  Creosoting 
liquor  or  heavy  oils  ;  they  are  taken  ex- 
clusively from  the  oils  lighter  than  water, 
which  last  have  never  been  employed  for 
the  Creosoting  process,  and  are  value- 
less for  timber-preserving.  The  benzols, 
toluols,  &c.,  from  which  the  aniline  dyes 
are  produced,  are  extremely  volatile,  like 
alcohol. 

The  heavy  oils  of  tar,  or  dead  oils 
heavier  than  water,  constitute  the  "  Cre- 
osote v  of  the  timber  yards.  They  con- 
tain numerous  substances,  some  of  them 
liquid,  some  semi-solid,  varying  consid- 
erably in  their  properties,  but  most  of 
them  are  now  recognized  as  antiseptics. 
Formerly,  the  whole  mass  of  these  heavy 
oils  was  used  for  timber -preserving  as 
they  were  collected  from  the  still,  but 
each  portion  can,  if  required,  be  separ- 


32 


ated  as  it  comes  over,  according  to  its 
volatility,  or  the  solid  matters  can  be 
separated  by  filtering,  for  subsequent 
treatment. 

It  has  been  seen  that  Mr.  Bethell's 
original  patent  recommended  the  use  of 
the  mother  liquor,  or  coal  tar,  thinned 
with  a  portion  of  heavy  coal-tar  oil.  So 
late  as  1849,  Bethell's  licenses  for  the 
use  of  his  patent  described  the  process 
as  "  saturating  timber  with  the  oils  ob- 
tained by  the  distillation  of  gas- tar, 
either  alone  or  mixed  with  gas-tar." 
The  author  remembers  how,  in  the  early 
days  of  Creosoting,  inspectors  frequently 
refused  to  allow  the  thinner  and  lighter 
dead  oils  to  be  used  without  being  thick- 
ened with  tar.  Tar,  the  mother  liquor, 
necessarily  included  all  the  substances 
contained  in  the  dead  oils,  plus  the  naph- 
thas and  the  pitch.  The  reasons  for  not 
adopting  the  tar  in  its  entirety  are  simply 
that  the  crude  naphthas  are  useless  as 
antiseptics,  and  would  immediately  evap- 
orate, whilst  the  pitch,  from  its  too  great 
solidity,  would  form  an  impediment  to 


33 


the  injection.  The  dead  oils,  therefore, 
came  into  use  alone,  and  there  crept  in- 
to some  of  the  specifications  the  contra- 
dictory prescriptions  that  the  wood  was 
to  be  Creosoted  according  to  Bethell's 
patent,  but  that  the  Creosote  was  to  be 
free  from  adulteration  with  coal  tar. 

The  dead  oils  made  in  London,  and  in 
all  places  where  the  tar  is  produced  from 
the  carbonization  of  the  coal  of  the 
Newcastle  district,  are,  as  compared  with 
other  dead  oils,  the  richest  in  semi-solid 
substances  (naphthalene,  anthracene,  py- 
rene,  &c.),  and  they  require  a  higher 
temperature  to  volatilize.  They  are  gen- 
erally called  "London  oils."  The  dead 
oils  of  the  Midland  Districts  are  lighter, 
thinner,  and  more  volatile,  and  contain 
usually  a  larger  proportion  of  the  ordi- 
nary tar  acids.  They  are  usually  called 
u  Country  oils/'  The  Scotch  oils  are, 
many  of  them,  still  lighter,  thinner,  and 
more  volatile,  sometimes  lighter  than 
water.  Some  Scotch  oils,  however,  have 
been  proved  to  be  of  excellent  quality. 

As  regards    the   question  of  thick  or 


34 

thin  oils,  there  is  no  doubt  as  to  the 
opinion  and  practice  of  the  earlier  intro- 
ducers of  the  Creosoting  process.  In 
January,  1853,  Mr.  Bethell  stated  that 
"  the  product  of  Newcastle  coal  contained 
a  quantity  of  naphthalene,  and  that  he 
was  an  advocate  for  its  use."  In  Novem- 
ber, 1864,  he  said  that  "the  Creosoting 
process  was  not,  as  often  described,  a 
chemical  process  entirely " ;  that  Creo- 
sote did  coagulate  albumen  in  the  sap  of 
the  wood ;  "  but  that  was  not  his  only 
idea  when  he  introduced  the  process : 
his  object  was  to  fill  the  pores  of  the 
wood  with  a  bituminous  asphaltic  sub- 
stance, which  rendered  it  waterproof," 
&c. 

The  late  Mr.  H.  P.  Burt,  whoselabors  in 
connection  with  the  preservation  of  tim- 
ber will  be  remembered  by  many  of  the 
elder  members  of  the  engineering  pro- 
fession, was  in  the  habit,  for  many  years, 
of  using,  by  preference,  the  heavy  Lon- 
don oils,  mixed  at  times  with  a  small  per- 
centage of  the  country  oils,  the  latter  as 
solvents  or  diluents  of  the  more  solid 


/ 

35 


material.  The  author,  whose  connection 
with  Mr.  Burt  commenced  in  1850,  re- 
members, among  his  first  experiences  of 
creosoting,  the  solid  masses  of  naph- 
thalene contained  in  the  tanks  before 
heating. 

When  the  construction  of  railways 
commenced  in  India  in  1850  and  1 851, 
it  was  speedily  discovered  that  the  tim- 
ber found  in  that  country  was  subject  to 
very  rapid  destruction  by  decay  and  by 
the  attacks  of  insects.  A  serious  difn- 
culty  was  encountered  by  engineers  in 
procuring  suitable  sleepers,  and  the  ex- 
periment was  tried  of  sending  creosoted 
Baltic  timber  from  this  country.  The 
first  consignment  of  this  material  was 
sent  out  in  December,  1851,  for 
the  East  Indian  Railway  Company. 
The  results  were  promising  from  the 
first,  and  the  exportation  of  creosoted 
sleepers  to  India  continually  increased. 
The  Minutes  of  Proceedings  of  this  In- 
stitution contain  numerous  records  of 
the  rapid  decay  of  unprepared  timber  in 
tropical  climates,  and  also  of  the  very 


36 


great  general  success  of  creosoted  timber 
exposed  to  the  same  influences,  check- 
ered, however,  with  a  few  instances  of 
partial  failure,  which  should  be  as  in- 
structive as  the  successes.  It  may  be 
interesting  to  refer  to  the  two  papers  by 
Mr.  Bryce  McMaster,  upon  Indian 
Permanent  Way  materials,  one  read 
in  1859,  and  the  second  in  1863,  in 
which  the  success  of  creosoted  timber 
in  India  is  fully  set  forth.  Mr.  Juland 
Danvers,  in  his  annual  report  to  the  Sec- 
retary of  State  for  India  for  the  year 
1863,  remarks  that  it  is  cheaper  to  send 
out  creosoted  Baltic  sleepers  than  to  use 
those  of  indigenous  wood.  The  printed 
report  of  the  East  Indian  Railway  Com- 
pany for  the  year  1867  again  records  the 
success  of  creosoted  sleepers,  after  six- 
teen years'  experience  of  their  use. 

It  becomes  a  matter  of  interest  to  as- 
certain the  kind  of  Creosote  which  was 
used  for  these  earlier  Indian  sleepers. 
When  the  exportation  first  began  there 
was  a  custom's  duty  upon  the  importa- 
tion of  Baltic  timber  into  this  country 


37 


equal  to  about  20  per  cent,  on  the  value 
of  the  sleepers.  The  author's  firm  made 
early  arrangements  for  creosoting  in 
bond,  and  for  this  reason,  and  with  tri- 
fling exceptions,  all  the  sleepers  sent 
abroad,  although  supplied  by  various 
contractors,  were  for  many  years  creo- 
soted  at  the  works  of  the  author's  firm 
at  Rotherhithe  and  at  the  Victoria  docks. 
Their  books  contain  accurate  records  of 
the  origin  of  all  the  creosote  used.  As 
may  be  anticipated,  by  far  the  greater 
bulk  was  London  oil,  up  to  1863  com- 
paratively little  country  oil,  and  in  some 
years  none  at  all  being  used.  In  Janu- 
ary, 1853,  Mr.  Burt,  in  describing  to  this 
Institution  the  process  which  he  used, 
spoke,  as  a  matter  of  course,  of  Creosote 
becoming  a  hard,  compact  mass  at  a  tem- 
perature below  35°  Fahrenheit.  Ten 
years  later,  in  February,  1863,  speaking 
with  reference  to  the  Creosoting  of  some 
sleepers,  the  success  of  which  in  India 
had  just  been  announced,  he  described 
Creosote  as  becoming  solid  at  a  tempera- 
ture below  40°  Fahrenheit,  and  added 


that,  in  consequence,  he  had  introduced 
a  heating  apparatus  inside  the  Creosoting 
cylinder. 

With  the  exception  of  a  small  experi- 
mental shipment  of  larch  and  Scotch  fir, 
all  the  sleepers  sent  to  India  have  been 
of  Baltic  fir  timber  from  the  Polish  and 
Russian  ports.  The  shipments  were  of 
the  ordinary  kind  of  wood,  such  as  was 
in  use  at  first  for  sleepers  in  this  country, 
and  were  mostly  of  triangular  section. 
Amongst  them,  for  the  first  three  or  four 
years,  were  considerable  quantities  of 
white-wood,  a  wood  somewhat  liable  to 
split  in  hot  countries.  Subsequently,  red- 
wood was  stipulated  for,  and  with  good 
reason,  in  all  Indian  specifications.  The 
quantity  of  Creosote  injected  into  these 
sleepers  was  at  first  from  35  to  40  gal- 
lons to  the  load  of  50  cubic  feet,  as  com- 
pared with  the  50  and  60  gallons  of  the 
present  day.  At  present  not  only  is  a 
larger  quantity  of  Creosote  injected,  but 
more  care  is  also  expended  in  the  selec- 
tion of  the  wood  than  was  formerly  the 
case.  If,  therefore,  the  earlier  sleepers 


39 


shipped  to  India  behaved  well,  it  might 
be  assumed  that  the  quality  of  the  Creo- 
sote, at  least,  was  suited  to  the  climate. 
Such  Creosote,  however,  as  was  then 
used  would  now  be  rejected  under  the 
requirements  of  many  of  the  specifica- 
tions at  present  in  force  for  the  prepara- 
tion of  timber  for  tropical  countries.  It 
is  a  question  for  grave  consideration 
whether  the  change  has  been  for  the  bet- 
ter. 

It  is  a  matter  of  notoriety,  that  for 
many  years  an  increasing  demand  has 
arisen  for  the  thinner  and  lighter  Creo- 
sotes. "  Country  oil  "  became  more  pop- 
ular, and  began  to  be  mentioned  in  speci- 
fications. Inspectors  preferred  these 
thinner  oils  ;  they  were  injected  with  less 
trouble,  and  the  timber  looked  cleaner 
and  less  "  muddy "  after  the  process, 
especially  in  the  winter,  when  the  Lon- 
don oils  are  more  solid.  Contrary  to  the 
opinion  of  the  introducers  of  Creosot- 
ing,  the  thin,  light  "  Country  oil  "  came 
to  be  considered  by  many  as  the  supreme 
type  of  excellence. 


40 


This  view  was  adopted  by  the  late  Dr. 
Letheby,  who  was  further  influenced  by 
the  growing  recognition  of  the  wonder- 
ful antiseptic  powers  of  carbolic  acid. 
Discovered  in  coal  tar  by  Runge,  a  Ger- 
man chemist,  in  1834,  carbolic  acid  had 
gradually  achieved  the  important  position 
which  it  still  holds  as  one  of  the  most 
valuable  of  antiseptics  for  sanitiry  and 
surgical  puposes.  Carbolic  acid  in  vary- 
ing quantities  was  present  in  the  tar  oils; 
the  other  constituents  of  those  oils  were 
imperfectly  understood ;  some  of  them, 
now  well  known,  had  not  then  been  dis- 
covered. The  success  of  the  creosoting 
process  was  therefore  by  a  priori  reason- 
ing attributed  mainly,  if  not  solely,  by 
Dr.  Letheby  to  the  presence  of  the  tar 
acids.  In  June,  1860,  Dr.  Letheby  pub- 
lished his  views  on  this  subject  in  the 
"Journal  of  the  Society  of  Arts."  He 
considered  carbolic  acid  to  be  the  most 
effective  constituent  of  the  tar  oils,  and* 
that  the  efficiency  of  the  latter  in  pre- 
serving timber  depended  ma;nly  upon 
the  percentage  of  carbolic  acid  which 


41 

they  contained.  He  therefore  concluded 
that  the  lighter  poitions  of  the  dead  oils 
were  the  best,  viz.,  those  portions  dis- 
tilling between  360°  Fahrenheit  and  490° 
Fahrenheit,  as  they  contain  the  tar  a^ids 
in  greatest  abundance.  Naphthalene  and 
para-naphthalene  he  desired  to  exclude 
as  much  as  possible,  as  he  held  them  to 
be  of  no  value  in  the  preparation  of  tim- 
ber. He  had  found  the  proportion  of 
carbolic  acid  in  tar  oils  to  range  from  6 
per  cent,  down  to  as  low  as  0.5  per  cent. 
In  a  letter  of  his  in  the  author's  posses- 
sion, dated  5th  June,  1863,  he  alludes  to 
two  samples  as  containing  "unusually 
large "  proportions  of  tar  acids ;  the 
"quantities  were  respectively  6.4  per  cent, 
and  10.1  per  cent.  In  a  lecture  at  Not- 
tingham, in  1867,  Dr.  Letheby  described 
a  specification  which  he  had  drawn  up 
for  an  Indian  railway.  This  specifica- 
tion, dated  1865,  contains  the  following 
stipulations :  The  creosote  is  to  have  a 
specific  gravity  as  near  to  1,050  as  pos- 
sible, ranging  from  1,045  to  1,055.  It  is 
not  to  deposit  naphthalene  or  para-naph- 


42 


thalene  at  a  temperature  of  40°  Fahren- 
heit. It  is  to  contain  5  per  cent,  of  crude 
carbolic  and  other  coal-tar  acids  (by  the 
caustic  potash  test).  It  is  to  yield  90 
per  cant,  of  liquid  oil,  when  distilled 
from  its  boiling  point  to  a  temperature  of 
600°  Fahrenheit. 

From  an  examination  of  upwards  of 
seventy  timber-preserving  specifications 
in  the  author's  possession,  ranging  from 
1849  to  the  present  year,  it  is  manifest 
that  a  new  departure  was  thus  inaugur- 
ated by  Dr.  Letheby.  For  the  first  time 
a  boiling-point  is  fixed,  a  certain  percent- 
age of  tar  acids  insisted  upon,  whilst  the 
use  of  naphthalene  and  the  heavier  dis- 
tillates is  discouraged.  This  specification 
has  long  ceased  to  be  used,  but  its 
stipulations  have  been  copied,  and  in 
some  cases  carried  to  greater  lengths,  in 
more  modern  specifications,  10  per  cent, 
of  tar  acids  being  occasionally  required. 
Such  specifications  exclude  the  London 
oils  if  taken  in  their  entirety  as  they 
come  from  the  still.  It  is  to  be  regret- 
ted that,  at  the  period  mentioned,  there 


43 


is  no  record  of  experiments  having  been 
made  by  any  English  chemists  as  to 
the  actual  effects  produced  upon  timber 
by  the  various  constituents  of  the  tar 
oils  taken  separately.  For  want  of  such 
a  test,  it  would  appear  that  an  import- 
ant element  in  the  question  was  for 
some  years  overlooked  in  this  country. 

So  early  as  1848  the  French  Academie 
des  Sciences  received  a  communication 
from  De  Gemini,  detailing  a  series  of 
experiments  upon  wood  prepared  with 
various  antiseptics.  This  investigator 
endeavored  to  prove  that  timber  cannot 
be  permanently  preserved  by  the  use  of 
antiseptics  which  are  themselves  soluble 
in  water,  and  for  that  reason  he  preferred 
the  use  of  heavy  oils,  or  bituminous 
substances.  The  Academie  rejected  the 
conclusions  of  De  Gemini,  more  especial- 
ly as  he  denied  that  solutions  of  sulphate 
of  copper  formed  insoluble  compounds 
with  woody  fiber. 

In  1862  Mr.  Kottier  presented  a  paper 
to  the  Academie  Royal  e  de  Belgique  giv- 
ing the  results  of  a  number  of  experi- 


44 


ments  as  to  the  effects  upon  timber  of 
the  various  constituents  of  coal-tar  oil. 
He  arrived  at  the  conclusion  that  al- 
though carbolic  acid  (L'Acide  Phenique) 
was  a  very  energetic  antiseptic,  yet  that, 
owing  to  its  volatility,  the  durable  success 
of  the  Creosoting  process  was  not  due 
to  its  agency.  He  attributed  that  suc- 
cess to  the  heavier  and  less  volatile  por- 
tions which  came  over  at  the  later 
periods  of  the  distillation,  and  consid- 
ered that  the  heavier  they  were  the 
better. 

Later  on  this  investigation  was  taken 
up  by  Mr.  Charles  Coisne,  who  was  then, 
and  still  is,  an  engineer  in  the  service  of 
the  Belgian  Government.  In  1863  Mr. 
Coisne  commenced  a  series  of  experi- 
ments, the  object  being  to  determine,  in 
a  practical  manner,  which  portions  of 
the  tar  oils  best  preserved  the  timber. 
The  results  were  so  instructive,  that  in 
1866  he  inaugurated  a  new  series  of  ex- 
periments, still  more  carefully  conducted, 
which  lasted  until  1870.  He  procured 
samples  of  Creosote  from  England,  Scot- 


45 


land,  Belgium  and  France.  Four  of  these 
samples  contained,  respectively,  15  per 
cent.,  15  per  cent.,  8  per  cent.,  and  7 
per  cent,  of  tar  acids  by  the  usual  test. 
The  fifth  was  an  oil  of  heavy  specific 
gravity,  specially  prepared,  and  contain- 
ing no  tar  acids.  Yet  this  last  sample 
produced  better  results  than  any  of  the 
others.  Each  sample  was  divided  into 
portions.  Wood  shavings  were  saturated 
with  these  oils  in  the  following  different 
ways : 

1st.  With  the  Creosotes  as  received. 

2d.  With  the  Creosotes,  supplemented 
by  additional  quantities  of  tar  acids. 

3d.  With  the  Creosotes,  supplemented 
by  some  of  the  heavier  portions  of  the 
same  oils  distilling  over  at  a  temperature 
exceeding  320°  Centigrade  (628°  Fahren- 
heit). 

4th.  With  the  original  Creosotes  di- 
vided into  the  lightest,  the  medium,  and 
the  heaviest  portions,  with  each  of 
which  the  shavings  were  separately  sat- 
urated. 

A  putrefying  pit  (pourrisoir)  was  pre- 


46 


pared,  in  which  the  shavings  were 
placed  on  the  10th  of  November,  1866, 
together  with  other  shavings  not  pre- 
pared. After  four  years'  sojourn  in  the 
pourrisoir,  they  were  removed  and  ex- 
amined on  the  16th  November,  1870. 
The  results  were  strikingly  in  favor  of 
the  heavier  oils,  and  adverse  to  the  tar 
acids,  which  last  bodies  appeared  to  have 
been  wholly  ineffective.  The  shavings 
which  had  been  prepared  with  the  light- 
est portions  of  the  oils,  although  they 
had  contained  the  largest  portions  of  the 
tar  acids,  were,  nevertheless,  in  the  worst 
condition.  Those  prepared  with  the  oils 
somewhat  heavier  were  in  most  cases 
better  preserved.  Best  of  all  were  the 
shavings  prepared  with  the  heaviest  oils, 
procured  by  distilling  at  the  higher  tem- 
peratures even  when  containing  no  tar 
acids ;  these  last  were  all  perfectly 
sound.  The  un-creosoted  shavings  were 
all  rotten.  Mr.  Coisne  believed  that  the 
best  portions  of  the  oils  were  the  "  green 
oils,"  distilling  at  high  temperatures. 
These  experiments  are  recorded  at 


47 


length  in  the  <l  Annals  des  Travaux 
Publiques  de  Belgique,"  also  in  separate 
pamphlets.  Their  results  have  consider- 
ably influenced  the  practice  of  railway 
engineers  on  the  Continent.  The  Belgian 
Government  accepted  the  conclusions 
arrived  at  by  Mr.  Coisne,  and  for  many 
years  has  based  its  creosoting  specifica- 
tions thereon,  with  highly  satisfactory  re- 
sults. The  specification  for  the  Belgian 
State  Railways  does  not  stipulate  for  any 
tar  acids  ;  it  requires  that  at  least  two- 
thirds  of  the  Creosote  must  have  been 
obtained  by  distillation  at  a  temperature 
exceeding  250°  Centigrade  (482°  Fahren- 
heit), and  the  remainder  at  a  tempera- 
ture exceeding  200°  Centigrade  (392° 
Fahrenheit).  It  allows  30  per  cent,  of 
naphthalene,  which  is  calculated  at  the 
ordinary  temperature.  In  a  recent  cor- 
respondence with  the  author,  Mr.  Coisne, 
who  has  for  more  than  twenty  years 
superintended  the  Creosoting  operations 
of  the  Belgian  Government,  confirms  the 
results  of  those  experiments  by  his  sub- 
sequent experience. 


48 


So  far,  the  experiments  and  the  experi- 
ence of  De  Gemini,  Rottier  and  Coisne 
appear  to  be  in  absolute  contradiction 
with  the  theory  that  the  Creosoting 
process  owes  its  success  to  the  tar  acids. 
Yet  the  fact  cannot  be  doubted,  that  the 
tar  acids  are  powerful  antiseptics,  and 
that  their  presence  arrests  decay.  What, 
then,  is  the  explanation  of  this  apparent 
anomaly  ? 

The  authorities  on  the  tar  acids  are 
many  and  reliable.  From  amongst  the 
learned  and  voluminous  treatises  which 
have  been  written  respecting  these 
bodies,  fifteen  references  have  been  made 
to  authors  in  England,  Scotland,  France, 
Belgium,  Germany  and  America.  None  of 
them  disagree  as  to  the  following  facts  : 
That  carbolic  acid  is  volatile  at  ordinary 
temperatures.  That  it  is  soluble  in  water. 
That  its  combinations  are  not  stable. 
That  it  is  a  powerful  germicide,  but  that 
its  efficacy  ceases  so  soon  as  it  evaporates 
or  is  washed  out  of  the  substances  in- 
tended to  be  preserved.  Professor  (now 
Sir  Joseph)  Lister,  whose  adoption  of 


49 

the  antiseptic  system  for  surgical  pur- 
poses has  revolutionized  hospital  prac- 
tice, speaks  from  his  large  and  valuable  ex- 
perience as  to  the  importance  of  carbolic 
acid  in  the  treatment  of  wounds,  but  he 
also  remarks  that  its  volatility  is  some- 
times an  evil  as  well  as  a  good.  Dr.  San- 
som,  whose  recent  work  on  antiseptics  so 
ably  epitomizes  the  results  arrived  at  by 
previous  investigators,  as  well  as  those 
due  to  his  own  researches,  speaks  of  it 
as  the  "aerial  disinfectant"  par  excel- 
lence. 

If  this  substance  can  be  washed  out 
by  water,  and  if  its  volatility  is  one  of 
its  great  merits,  and  occasionally  a  de- 
fect, for  sanitary  purposes,  can  it  at  the 
same  time  be  considered  as  a  durable 
agent  amongst  the  oils  injected  into  rail- 
way sleepers  ?  Especially  can  this  be  the 
case  in  those  tropical  countries  where 
extreme  heat  or  torrential  rains,  or 
alternations  of  both,  are  prevalent  1  For 
piles  and  other  timbers  used  for  harbor- 
work,  the  comparative  solubility  in  water 
of  the  antiseptic  agents  employed  is 


50 

also  a  matter  of  vital  importance.  What 
is  true  respecting  carbolic  acid,  will  also 
apply,  to  a  great  extent,  to  cresylic  acid, 
the  last  substance  being,  however,  some- 
what less  volatile  and  less  soluble  than 
the  former.  Do  these  bodies  become 
stable  by  entering  into  combination  with 
woody  fiber?  Their  instability  in  this 
connection  is  apparently  pointed  out  by 
Mr.  Coisne's  experiments.  It  may,  how- 
ever, be  objected  that  these  experiments 
were  not  conducted  under  the  conditions 
to  which  railway  timbers  are  exposed. 
This  point  also  has  been  very  fully  in- 
vestigated. 

In  1867  Mr.  Coisne  obtained  some 
Creosoted  sleepers  which  had  success- 
fully resisted  decay  during  periods  of 
from  eighteen  to  twenty  years.  The 
wood  was  crushed,  and  the  substances 
obtained  therefrom  tested.  He  found  no 
tar  acids  ;  if  they  had  ever  been  there, 
they  were  no  longer  present.  He  found, 
however,  a  quantity  of  naphthalene ;  also 
of  an  oil  which  did  not  commence  to  dis- 


51 


til  until  230°  Centigrade  (446°  Fahren- 
heit). 

In  1882  the  author  caused  some  simi- 
lar experiments  to  be  made.  Through 
the  kindness  of  the  authorities  of  the 
London  and  North-Western  Railway 
Company,  eleven  pieces  of  old  Creosoted 
sleepers  were  sent  from  their  permanent 
way.  They  had  been  in  use  for  the  fol- 
lowing periods : 

1  specimen 16  years. 


.17 
.20 
.22 
.28 
.29 
.30 
.32 


Sleepers  were  also  received  from  the 
Taff  Vale  Railway,  the  South- Eastern 
Railway,  and  the  Great  Eastern  Railway, 
which  had  been  in  use  periods  varying 
from  fourteen  to  twenty-three  years.  A 
portion  was  also  taken  from  a  Creosoted 
pale  fence,  which  had  been  fixed  in  the 
Victoria  docks  in  1855,  and  which  is  still 
in  place,  perfectly  sound  and  strong, 


52 


after  twenty-nine  years'  use.  A  careful 
analysis  of  these  seventeen  specimens, 
all  of  ordinary  Baltic  fir,  gave  the  follow- 
ing results : 

1st.  In  no  cases  were  any  tar  acids  de- 
tected by  the  ordinary  tests. 

2d.  In  fourteen  out  of  the  seventeen 
specimens  the  semi-solid  constituents  of 
the  tar  oils  were  present;  in  twelve  of 
them  was  naphthalene,  this  body  being 
in  some  cases  in  considerable  quantity. 

3d.  Only  small  percentages  remained 
of  oils  distilling  below  450°  Fahrenheit. 
In  the  majority  of  instances  from  60  per 
cent,  to  75  per  cent,  of  the  total  bulk  of 
substances  retained  in  the  wood  did  not 
distil  until  after  a  temperature  of  600° 
Fahrenheit  was  reached. 

It  is  clear,  therefore,  that  these  tim- 
bers had  been  preserved  by  the  action  of 
the  heaviest  and  most  solid  portions  of 
the  tar  oils,  and  that  the  other  constitu- 
ents had  disappeared. 

4th.  In  some  of  these  specimens 
acridine  was  searched  for  and  detected. 
This  substance  is  one  of  the  alkaloids  or 


53 

bases  now  known  to  exist  in  the  Creosote 
oils.  This  is  probably  the  first  occasion 
upon  which  acridine  has  been  publicly 
mentioned  in  connection  with  the  injec- 
tion of  wood ;  but  the  author  is  per- 
suaded that  it  will  come  to  be  recognized 
as  one  of  the  most  valuable  constituents 
of  the  tar  oils  for  timber-preserving 
purposes.  It  was  discovered  by  Graebe 
and  Caro  ;  it  is  a  powerful  germicide, 
and  solidifies  within  the  pores  of  the 
timber,  from  which  it  neither  evaporates 
nor  washes  out.  It  is  intensely  acrid 
and  pungent. 

Portions  of  the  same  specimens  of 
wood,  fifteen  in  number,  were  sent  to 
Mr.  Greville  Williams,  whose  original 
researches  with  relation  to  coal  deriva- 
tives have  been  for  so  many  years  known 
to  the  scientific  world.  Mr.  Greville 
Williams  tested  the  samples  of  wood  for 
tar  acids,  naphthalene,  and  the  alkaloids. 
For  the  tar  acids  he  found  all  ordinary 
tests  fail,  until  he  employed  the  extreme- 
ly delicate  one  by  bromine  and  ammonia. 
In  some  cases,  even  by  this  test,  no 


54 

phenols  could  be  detected,  but  in  most 
cases  he  succeeded  in  detecting  faint 
traces  of  those  bodies ;  generally  less 
than  one  part  in  three  thousand  ;  minute 
portions,  probably  of  the  heaviest  par- 
ticles of  the  tar  acids  which  had  been 
incorporated  and  retained  by  the  heavier 
portions  of  the  oils.  It  is  needless  to 
say  that  these  infinitesimal  quantities 
could  be  of  no  practical  value  in  preserv- 
ing the  wood.  In  all  the  specimens,, 
save  two,  he  found  naphthalene.  The 
presence  of  the  antiseptic  alkaloids  was 
distinctly  proved,  and  one  of  these 
bodies,  called  cryptidine,  which  he  had 
discovered  in  Creosote  oils,  in  1856,  was 
detected  by  him  in  one  of  the  specimens. 
Mr.  Greville  Williams  concludes  that 
the  preservative  action  of  the  Creosote 
oils  is  due  more  to  the  bases  or  alkaloids 
than  to  the  tar  acids,  as  the  former  re- 
main after  the  latter  have  disappeared. 
These  researches  were  published  in  the 
"  Journal  of  Gas  Lighting,"  and  also  in  a, 
pamphlet  in  the  possession  of  this  Insti- 
tution. 


55 

First,  and  most  volatile  of  all  the  Cre- 
osote oils,  are  the  carbolic  and  cresylic 
acids,  which  are  also  freely  soluble  in 
water  at  ordinary  temperatures ;  they 
come  over  from  the  still,  incorporated 
with  the  lightest  portions  of  the  oils. 
Pure  carbolic  acid  would  entirely  disap- 
pear by  evaporation,  if  not  secured  in  a 
stoppered  bottle.  Next  in  order  comes 
naphthalene,  which  is  much  less  volatile 
than  the  tar  acids.  It  is  not  soluble  in 
cold  water,  and  almost  insoluble  in  boil- 
ing water.  As  it  comes  from  the  still  it 
is  of  a  yellowish  color,  and  mixed  with 
the  heavy  oils,  it  gradually  becomes  black 
on  exposure  to  the  atmosphere.  It  forms 
the  principal  constituent  of  the  thick, 
muddy-looking  substance  which  some- 
times forms  on  the  surface  of  Creosoted 
timber,  and  which  may  often  be  seen  ad- 
hering to  the  ends  of  railway  sleepers  for 
several  years  after  they  have  been  placed 
in  the  line.  When  sublimed  by  the  ac- 
tion of  heat  and  a  current  of  air,  it  forms 
the  beautiful  frost-like  substance  well 
known  in  Creosoting  yards.  It  becomes 


56 


quite  solid  at  a  low  temperature,  and  in 
that  condition  would  be  an  impediment  to 
the  injection  of  the  timber — a  difficulty 
removed  by  heating  the  oils  to  about  100° 
Fahrenheit,  at  which  temperature  naph- 
thalene becomes  liquid.  After  injection 
it  solidifies,  and  greatly  assists  in  filling 
up  the  pores  of  the  wood. 

The  following  simple  experiments, 
which  have  been  tried  and  repeated  in 
many  different  ways  at  the  author's  lab- 
oratories during  the  last  few  years,  are 
in  strict  accordance  with  the  now  well- 
known  characteristics  of  naphthalene  and 
the  tar  acids : 

1.  If  tar    acids    and   naphthalene    be 
separately  exposed  either  at  the  ordinary 
temperature,  or  at   the   tropical   heat  of 
130°  Fahrenheit,  the  tar  acids  will  evap- 
orate with  much  more   considerable  ra- 
pidity than  naphthalene. 

2.  Injected  into  timber  the  same  results 
follow. 

3.  Light,  thin    oils,   containing    large 
percentages  of  tar  acids,  evaporate  more 
quickly  than  heavier  oils  containing  less 


57 


tar  acids  and  more  naphthalene,  when 
tested  by  methods  Nos.  1  and  2. 

In  weighing  after  these  experiments 
great  care  must  be  taken  to  allow  for  the 
absorption  of  moisture  from  the  atmos- 
phere. The  tar  acids  absorb  moisture 
before  finally  evaporating.  Wood  also 
absorbs  a  large  amount  of  moisture  when 
injected  with  oils  containing  these  acids. 

4.  By  repeated  washings  with  cold 
water,  all  the  carbolic  acid,  and  all  or  near- 
ly all  the  cresylic  acid,  can  be  washed  out, 
both  from  country  and  from  London  oils. 
These  experiments  assume  especial  im- 
portance in  considering  the  durable  ef- 
fects of  various  kinds  of  creosote  for 
protecting  timber  immersed  in  sea-water 
from  the  attacks  of  marine  insects. 

Dr.  Meymott  Tidy  has  published  the 
results  of  his  experiments  upon  naph- 
thalene. He  injected  pieces  of  wood 
with  this  substance,  and  exposed  them 
to  a  temperature  of  150°  Fahrenheit. 
He  found  that  the  evaporation  was  only 
superficial,  and  that  it  practically  ceased 
after  forty-eight  hours,  the  naphthalene 


58 

below  the  surface  remaining  within  the 
pores  of  the  wood.  Naphthalene  is  now 
recognized  as  an  antiseptic,  not  so  pow- 
erful in  its  immediate  effects  as  the  tar 
acids,  but  more  durable.  It  is  probable 
that  tar  acids  of  a  heavier  and  less  vola- 
tile type  than  carbolic  or  cresylic  acids, 
may  be  more  reliable  as  antiseptics  for 
preserving  timber. 

Following  in  the  series  of  distillates, 
amongst  the  Creosote  oils  are  the  alka- 
loids or  bases  of  the  quinoline  or  leuco- 
line  group,  amongst  which  chemists  are 
searching,  not  without  fair  promise  of 
success,  for  a  febrifuge  similar  to,  if  not 
identical  with,  the  quinine  derived  from 
the  cinchona  plant.  In  this  group  oc- 
curs the  substance  called  cryptidine,  al- 
ready alluded  to  as  one  of  the  valuable 
antiseptics  discovered  in  those  portions 
of  the  oils  which  were  formerly  character- 
ized as  "inert.'' 

Para-naphthalene,  mentioned  in  Dr. 
Letheby's  specification,  has  since  then 
become  the  basis  of  one  of  the  most  in- 
teresting chemical  discoveries  of  the  age. 


59 


It  was  excluded  by  Dr.  Letheby  from 
the  oils  intended  for  timber  preserving, 
and  is  probably  without  value  for  that 
purpose.  It  is  now  called  anthracene, 
and  is  extremely  valuable  as  the  sub- 
stance from  which  alizarine  is  manufac- 
tured, thanks  to  the  brilliant  discoveries 
of  Perkin  in  England,  and  of  Graebe, 
Liebermann  and  Caro  in  Germany.  Ali- 
zarine is  the  coloring  matter  used  by 
Turkey-red  dyers  and  printers  ;  for  ages 
it  had  been  extracted  from  the  madder 
root.  It  is  now  made  from  the  coal-tar 
product  anthracene,  of  a  far  higher  degree 
of  purity,  and  at  an  enormously  de- 
creased cost.  The  madder  root  has  gone 
almost  entirely  out  of  cultivation.  The 
quantity  of  anthracene  contained  in  tar 
is  relatively  small. 

Amongst  the  green  oils,  distilling  be- 
tween 550°  Fahrenheit  and  750C  Fahren- 
heit, is  found  the  acridine  already  al- 
luded to  as  a  valuable  germicide  and 
stable  antiseptic.  Phenanthrene,  carba- 
zol,  pyrene,  chrysene  and  benzerythrene, 
by  no  means  complete  the  list,  which  is 


60 


constantly  being  added  to  by  new  dis- 
coveries of  the  numerous  bodies  in  which 
these  dead  oils  are  so  prolific.  The 
properties  of  many  of  these  heavier 
bodies  are  still  imperfectly  under- 
stood ;  but  from  the  fact  that  they  will 
not  evaporate  except  at  exceedingly 
high  temperatures,  they  are  valuable  in- 
gredients for  timber-preserving. 

By  the  light  of  the  evidence  now  ac- 
cumulated, it  may  be  advisable  to  review 
the  question  as  to  the  relative  value  of 
these  various  bodies  contained  in  the 
heavy  oils  as  regards  the  preservation  of 
timber.  Some  of  them  are  becoming 
valuable  for  other  purposes.  Which  of 
them  should  the  engineer  retain  for  in- 
jecting wood? 

Can  the  conclusion  be  resisted,  that 
for  this  purpose  the  efficacy  of  the  tar 
acids  has  been  overrated,  and  this  at 
the  expense  of  the  more  stable  and  en- 
during portions  of  the  tar  oils  ?  The 
London  oils  as  they  come  from  the  still 
are  not  sufficiently  volatile  to  meet  the 
exigencies  of  some  modern  specifica- 


61 

tions,  nor  do  they  comply  with  these 
exigencies  as  regards  the  percentage  of 
tar  acids.  They  do  not,  as  a  rule,  contain 
more  than  from  4  to  7  per  cent,  of  tar 
acids,  and  they  will  not  yield  90  per 
cent,  of  their  bulk  by  distillation  below 
600°  Fahrenheit.  Therefore  a  pressure 
is  put  upon  the  manufacturer  to  meet 
the  fashion  by  "  taking  out ''  some  of  the 
heavier  portions,  and  in  some  instances 
this  is  done.  By  this  means  the  bulk  is 
rendered  lighter,  and  the  proportion  of 
tar  acids  to  the  diminished  bulk  is  in- 
creased. For  these  heavier  portions,  es- 
pecially for  the  green  oils,  a  market  is 
found  for  lubricating  and  other  pur- 
poses. But  in  the  author's  judgment  the 
efficacy  of  the  oils  as  antiseptics  for 
wood  is  thereby  diminished.  The  green 
oils,  after  the  anthracene  has  been  re- 
moved from  them  by  filtration,  should  be 
returned  to  the  Creosote  tank.  The  per- 
centage of  tar  acids  to  be  used  remains  a 
contested  matter  of  opinion.  But  the 
author  ventures  to  express  the  hope  that 
at  least  the  lighter  portions  of  the  tar 


62 


acids,  and  especially  carbolic  acid,  may 
soon  be  relegated  altogether  to  their 
important  functions  as  sanitary  antisep- 
tics, for  which  they  are  so  valuable,  in- 
stead of  being  wasted  by  the  attempt  to 
use  them  as  antiseptics  for  timber,  for 
which  their  peculiar  properties  render 
them  unreliable.  Upon  the  whole  it 
would  be  wiser  to  revert,  to  a  larger  ex- 
tent and  with  increased  knowledge,  to 
the  plan  of  using  the  London  oils  mixed 
with  the  country  oils,  and  encouraging 
instead  of  discouraging  the  use  of  the 
heavier  portions.  The  whole  of  the 
Creosote  oils  manufactured  from  ordi- 
nary gas  tar  in  this  country  are  required 
for  preserving  timber,  and  to  exclude 
one  considerable  portion  of  the  supply  is 
to  enhance  unnecessarily  the  cost  of  the 
rest.  No  oils,  however,  should  be  used 
as  Creosotes  which  are  lighter  than 
water.  Both  bone  oil  and  shale  oil  are 
sometimes  offered  as  Creosote  oils. 

In  1881  Professor  (now  Sir  Frederick) 
Abel  and  Dr.  Tidy  drew  up  a  joint 
Creosoting  specification,  in  which,  as  the 


63 


result  of  direct  experiment,  they  resolved 
to  exclude  no  semi-solid  bodies  which 
completely  melt  at  100°  Fahrenheit. 
They  further  changed  the  standard  of 
volatility  from  90  per  cent,  at  600° 
Fahrenheit  to  75  per  cent.  Subsequent 
and  prolonged  investigation  induced  Dr. 
Tidy  to  go  still  further  in  the  same  direc- 
tion, and  not  only  to  withdraw  the 
clause  limiting  to  2o  per  cent,  the  oils 
distilling  at  a  higher  point  than  600° 
Fahrenheit,  but  even  to  require  that  at 
least  25  per  cent,  of  those  non-volatile 
oils  must  be  present.  The  author's  ex- 
perience leads  him  entirely  to  agree  with 
the  progress  made  in  this  direction. 

CONFLICTING  THEORIES  ON  PUTREFACTION — 
THE  GERM  THEORY. 

If  experiment  and  experience  should 
lead  to  clearer  views  as  to  the  relative 
value  of  various  antiseptics,  it  may  be 
advisable  to  test  those  views  by  refer- 
ence to  the  recent  development  of  theory 
upon  the  causes  of  decomposition  in  or- 
ganized bodies.  How  do  antiseptics  act. 


64 


upon  timber  ?  Is  the  coagulation  of 
albumen  a  sufficient  explanation  of  their 
preservative  action  ?  Surely  not.  Many 
substances,  boiling  water  included,  which 
will  effectually  coagulate  albumen,  will 
not  prevent  the  decay  of  wood.  Coagu- 
lation retards,  but  does  not  prevent,  the 
decay  of  albumen  itself.  Again,  the 
quantity  of  albumen  in  fir  timber  is  ex- 
ceedingly small,  if  the  tree  be  cut  down, 
as  it  generally  is  and  always  should  be, 
during  the  season  when  the  sap  is  not 
circulating.  From  a  number  of  experi- 
ments made  upon  ordinary  fir  sleepers, 
the  author  arrives  at  the  conclusion,  that 
the  quantity  of  nitrogenous  matter  or 
albumen  which  they  contain  does  not 
usually  much  exceed  1  per  cent,  of  their 
weight.  Any  watery  fluid  containing 
from  "2  to  3  per  cent,  of  tar  acids  would 
effectually  coagulate  this  quantity  of 
albumen.  In  some  cases  it  is  found 
that  a  portion  of  this  albumen  is  actu- 
ally coagulated  by  substances  naturally 
contained  in  the  timber.  But  the  coagula- 
%tion  does  not  of  itself  preserve  the  wood. 


65 


Leibig's  theory  of  decomposition  has  al- 
readj  been  alluded  to.  He  maintained 
that  putrefaction  was  due  to  eremacausis 
or  slow  combustion,  produced  by  con- 
tagion, the  infected  bodies  communicat- 
ing a  molecular  motion  to^  the  atoms 
of  the  bodies  with  which  they  come  in 
contact,  and  that  these  phenomena  are 
not  caused  by  the  action  of  germs  or 
living  organisms. 

The  modern  germ  theory  distinctly 
traverses  this  last  assertion.  Pasteur 
affirms,  that  without  the  presence  of  liv- 
ing germs,  the  phenomena  of  organic 
decomposition  do  not  accomplish  them- 
selves, and  that  these  germs  are  the 
veritable  agents  of  the  decomposition. 
The  laborious  experiments,  and  the  lucid 
deductions  of  Professor  Tyndall  con- 
firm the  experiments  and  theories  of 
Pasteur.  Professor  Tyndall  explains 
that  the  air  is  laden  with  clouds  of  germs, 
agents  of  decomposition,  ever  ready  to 
settle  down  and  develop  upon  matter 
suitable  to  their  growth.  He  finds  that 
the  contents  of  tubes  filled  with  the 


66 

most  putrescible  materials,  animal  or 
vegetable,  can  be  preserved  from  putre- 
faction indefinitely,  by  the  exclusion  of 
germs.  But  that  it  is  not  sufficient 
merely  to  poison  or  neutralize  one  gen- 
eration of  organisms,  the  incursions  of 
fresh  myriads  must  be  excluded,  or  putre- 
faction will  ensue. 

After  reading  the  "Essays  on  the 
Floating  Matter  of  the  Air,"  in  which  . 
Professor  Tyndall  describes  how  the 
germs  gradually  fell  into  the  open  tops 
of  the  test  tubes,  let  the  comparison  be 
made  between  the  mouths  of  these  tubes 
and  the  gaping  orifice  of  a  crack  pro- 
duced by  the  sun  in  a  piece  of  timber. 
Through  it  the  germs  will  descend,  and 
if  there  is  nothing  to  arrest  their  action, 
and  if  the  crack  is  deeper  than  the  por- 
tion of  the  wood  charged  with  antisep- 
tics, they  will  carry  destruction  into  the 
center  of  the  log.  But  if  the  antiseptic 
be  of  an  oily  or  bituminous  nature,  it 
will  flow  into  the  cracks  when  they  first 
develop  themselves,  and  seal  up  the  ori- 
fices against  the  enemy.  Examine  a 


67 

crack  or  a  wound  in  the  trunk  of  a  living 
fir  tree ;  it  will  be  found  that  by  a  nat- 
ural process,  a  resinous  substance  ex- 
udes, which  closes  the  wound  against  the 
agents  of  destruction. 

The  bodies  of  mammoths  preserved  in 
ice  through  countless  ages,  the  trees  of 
primeval  forests  excluded  from  the  air 
beneath  thick  deposits  of  peat,  the  frag- 
ments of  wooden  piles  which  have  en- 
dured undecayed  for  centuries  when 
driven  deeply  below  the  surface  of 
water,  all  confirm  the  experiments  of 
Pasteur  and  Tyndall,  and  prove  that  the 
exclusion  of  germs  prevents  patref ac- 
tion. Specimens  are  exhibited  of  a 
wooden  pile  from  the  remains  of  the 
bridge  (destroyed  by  fire)  which  was 
constructed  by  Charlemagne  across  the 
Rhine  at  Mayence ;  of  pieces  of  piles 
from  the  foundations  of  the  bridge  across 
the  Medway  at  Rochester,  which  was  de- 
stroyed by  Simon  de  Montfort  in  1264, 
and  which  was  probably  then  about  one 
hundred  years  old  ;  also  from  the  new 


68 

bridge  erected  to  replace  the  former  one 
in  1283. 

It  is  not  for  the  author  to  draw  the 
dividing  line  between  the  decomposing 
action  of  germs  and  the  action  of 
oxidation.  It  is  sufficient  for  his 
purpose  to  submit  that  all  influences 
which  either  destroy  or  exclude  germs, 
will  prevent  decay  so  long  as  those  influ- 
ences endure ;  but  that  permanent  ef- 
fects must  not  be  relied  upon  from  agents 
which  are  not  themselves  permanent  and 
abiding.  The  germ  theory  then  becomes 
a  severe  but  a  salutary  test  in  choosing 
antiseptics  for  the  treatment  of  timber. 
Such  treatment  is  of  little  value  unless 
its  effects  will  endure  for  long  periods. 
Reliance,  therefore,  must  not  be  placed 
upon  those  germicides,  however  potent, 
which  will  readily  volatilize  in  air,  or 
dissolve  in  water.  A  growing  skepticism 
arises  from  experience  as  to  insoluble 
compounds  being  formed  between  woody 
fiber  and  substances  which  are  them- 
selves soluble  in  water.  In  short,  the 
substances  to  be  employed  should  by 


69 


preference  be  antiseptics  in  a  double 
sense  ;  they  should  be  both  germicides 
and  germ  excluders.  From  the  long 
list  of  germicides  must  be  especially  ex- 
cluded such  as  injure  or  weaken  the 
fiber  of  the  wood  ;  amongst  these  latter 
must  be  classed  all  solutions  with  very 
strong  acid  or  alkaline  reactions  ;  also 
some  of  the  metallic  salts.  It  has  been 
seen,  that  the  salts  of  zinc,  mercury,  and 
copper  have  been  to  some  extent  suc- 
cessful ;  of  these  the  author's  experience 
induces  him  to  prefer  sulphate  of  cop- 
per, as  less  soluble  in  water  than  chloride 
of  zinc,  and  not  volatile  like  corrosive 
sublimate.  Even  sulphate  of  copper  can- 
not be  permanently  relied  upon,  when 
exposed  to  the  continuous  action  of 
water  ;  but  it  may  be  found  useful  in 
comparatively  dry  situations,  or  as  a  pro- 
tection against  dry-rot  to  timber  under 
cover.  From  its  properties  as  a  germi- 
cide, sulphate  of  copper  might  be  use- 
fully employed  in  conjunction  with  oily 
or  bituminous  fluids,  even  with  oils 
which  do  not  possess  great  potency  as 
germicides. 


70 


From  all  research  and  experience  it 
would,  however,  appear  that  the  same 
conclusions  may  be  derived,  viz.,  that  the 
best  antiseptics  for  timber  are  to  be 
found  amongst  oils  and  bitumens  which 
fill  up  the  pores  of  the  wood.  Of  such 
bodies,  those  which  contain  germicides 
are  to  be  preferred.  And,  other  proper- 
ties being  equal,  those  which  either  sol- 
idify in  the  pores  of  the  wood  or  which 
require  an  extremely  high  temperature 
to  volatilize  them,  and  which  are  insol- 
uble in  water,  must  surely  be  the  best 
of  all. 

Apparatus  for  Timber -Preserving. — 
Of  the  apparatus  employed  for  applying 
antiseptics  to  wood,  the  most  ancient  and 
the  most  popular  is  the  tar  brush  or  the 
paint  brush.  During  the  last  century, 
and  in  the  earlier  portion  of  the  present, 
steeping  in  tanks  was  extensively  adopted, 
the  various  liquids  being  employed  either 
cold  or  heated.  A  marked  improvement 
was  introduced  in  1831  by  Mr.  Breant,  a 
director  of  the  ATint  of  Paris,  who  in- 
vented the  first  apparatus  for  injecting 


71 


timber  by  means  of  vacuum  and  press- 
ure, in  a  closed  iron   cylinder ;  he  em- 
ployed,  by   preference,  linseed   oil   and 
resin.     The  cylinder  was  fixed  vertically, 
an  inconvenient  arrangement  not  neces- 
sary to  the  efficiency  of  his  process.  The 
iron  cylinder  and  the    process  by  vacu- 
um and  pressure   were   adopted  by  Mr. 
Bethell,  and  greatly  improved  by  him  and 
by  Mr.  H.  P.  Burt,  who  were  associated 
together  for  some  years.     The  cylinder 
was  enlarged,  its  fittings  strengthened  and 
simplified,  and  an  interior  heating  appa- 
ratus   added.      In   Mr.   Burt's  paper  of 
January,  1853,  there  is  a  full  description 
of  this  machinery ;  its  main  features  are 
still  the    same  in  the   usual   Creosoting 
apparatus   of    the  present   day.      These 
cylinders,  being  of    wr ought-iron,   were 
applicable  to  Creosote  oils  and  to  chlor 
ide    of  zinc,  but  not    to   salts  having  a 
corrosive  action  upon  iron,  such  as  sul- 
phate of  copper  and  corrosive  sublimate. 
In  1842,  Mr.  Timperley  described  to  this 
Institution    a    method     which    he    had 
adopted  on  the  Hull  and  Selby  Railway, 


72 

for  lining  the  iron  cylinder,  in  order  to 
preserve  it  from  the  action  of  corrosive 
sublimate.  This  method  and  the  expedient 
of  smearing  the  inner  surface  with  pitch 
were  proposed  and  tried  for  sulphate  of 
copper  injections  with  but  partial  suc- 
cess. The  author  had  several  cylinders 
materially  injured  or  destroyed  by  the 
corrosive  action  of  these  salts.  In  1857 
Messrs.  Lege  and  Fleury  Peronnet  in- 
troduced an  apparatus  of  which  the  cyl- 
inder, trucks  and  pressure  pumps  were 
entirely  of  copper,  and  machinery  of  this 
costly  description  is  still  used  for  the 
Compagnie  des  Chemins  de  Fer  du  Midi, 
at  Labouheyre.  In  1865  the  author  took 
out  a  patent  for  the  following  apparatus  : 
Inside  the  iron  cylinder  he  placed  a 
wooden  tank,  which  contained  the  timber 
to  be  operated  upon,  and  in  which  was 
the  sulphate  of  copper  solution.  It  was 
an  open  wooden  tank,  inside  a  closed 
iron  cylinder.  The  pressure  applied  was 
that  of  condensed  air,  a  condensing  air- 
pump  being  used,  capable  of  maintain- 
ing an  effective  pressure  of  200  Ibs.  to 


73 


the  square  inch.  By  this  means  the  tim- 
ber was  injected  with  the  copper  solu- 
tion without  injury  to  the  iron  cylinder. 

The  process  of  Dr.  Boucherie  was  at 
one  time  largely  used  in  France.  It  con- 
sisted in  the  injection  of  newly-fallen 
timber  in  the  forest  by  the  vertical  press- 
ure of  a  column  of  the  antiseptic  solu- 
tion, generally  sulphate  of  copper,  which 
was  conducted  through  a  pipe  from  a 
small  reservoir  fixed  at  a  height  of  30  or 
40  feet.  The  tube  was  attached  by  an 
ingenious  arrangement  to  the  end  or 
middle  of  the  log ;  the  antiseptic  liquid 
expelled  the  sap  from  the  softer  parts  of 
the  timber,  and  took  its  place.  The 
process  is  still  used  to  a  small  extent  in 
France,  principally  for  telegraph  poles. 

Various  attempts  have  been  made  to 
imbue  timber  with  the  vapors  of  oils, 
either  by  employing  the  tensions  of  the 
vapors  themselves,  or  by  the  use  of  the 
pressure-pump.  The  first  experiment  of 
this  kind  appears  to  have  been  made  by 
Lukin,  in  the  dockyard  at  Woolwich  in 
1812,  when  the  apparatus  exploded,  with 


74 


fatal  consequences  to  the  workmen  em- 
ployed, and  the  attempt  was  abandoned. 
The  patents  of  Franz  Moll  in  1836,  of 
Bethell  in  1864,  and  other  subsequent 
patents,  claim  the  invention  of  the  prin- 
ciple of  injecting  Creosote  oils  in  a  state 
of  vapor.     If  this  could  be  conveniently 
or  safely  carried  out,  the  system  might 
possess   some    advantages.       But  there 
is  a  fatal  objection  to  its  employment. 
Timber  is  weakened    by  exposure  to  a 
temperature  much  exceeding  250°Fahren- 
heit,  whilst  at  300°  Fahrenheit,  or  a  little 
above,  it  commences  to  decompose,  and 
becomes   seriously    injured.      Now    the 
boiling  point  of  the  Creosote  oils  ranges 
from  a  little  below  400°  Fahrenheit  up  to 
760°  Fahrenheit.      As  with  the  steam  of 
water,  so  is  it  with  the  vapor  of  oils — no 
pressure  can  be  obtained  with  them,  ex- 
cept  at   a   temperature   exceeding  their 
boiling  point.     The  vapors  of  the  Creo- 
sote oils  cannot,  therefore,   be  injected 
into  timber  except  at  temperatures,  and 
under    conditions    of     pressure,    which 
would  destroy  the  value  of  the  timber  as 


75 


an  engineering  material.  The  process 
has  been  tried  in  France,  and  it  failed, 
owing  to  the  complete  deterioration  of 
the  timber. 

A  modification  of  this  system  has, 
however,  been  carried  into  practice. 
Super-heated  steam  was  passed  through 
Creosote  oils,  and  then  injected  into  the 
sleepers  (which  had  been  previously 
warmed  by  steam)  with  the  idea  that 
the  mingled  vapors  of  water  and  Creo- 
sote might  be  injected  into  the  timber 
at  a  temperature  of  from  290°  Fahren- 
heit to  320°  Fahrenheit.  With  this 
modified  process,  the  author's  firm  carried 
out  some  extensive  operations  for  the 
Compagnie  des  Chemins  de  Fer  de 
1'Ouest,  it  being  the  desire  of  the  engi- 
neers of  that  company  to  economize  the 
Creosote,  and  to  try  whether  in  a  finely 
divided  state,  a  smaller  quantity  might 
not  suffice  by  being  more  deeply  injected. 
The  operation  was  supplemented,  how- 
ever, by  an  injection  of  Creosote  in  the 
usual  fluid  state. 

After  prolonged  trials,   the  first  part 


76 


of  the  operation  was  discontinued  by 
order  of  Mr.  Bouissou,  the  company's 
engineer  of  the  permanent  way.  It  was 
found,  whenever  the  cylinder  was  opened 
before  the  second  operation,  that  a  small 
portion  of  the  lightest  particles  of  the 
Creosote  had  been  carried  over  mechani- 
cally into  the  cylinder  by  the  super- 
heated steam.  Once  within  the  cylinder, 
however,  the  two  fluids  obeyed  the  laws 
which  govern  their  respective  volatili- 
ties :  the  Creosote  oil  sank  to  the  bot- 
tom of  the  cylinder,  and  the  vapor  of 
water  only  was  injected  into  the  timber. 
The  sleepers  on  examination  and  testing 
by  the  ordinary  tests,  contained  neither 
tar  oils  nor  tar  acids. 

An  analogous  experiment  tried  at  the 
Timber  Preserving  Works  of  the  Austrian 
North- West  Railway,  is  described  in  the 
journal  of  the  Architects  and  Engineers' 
Institute  of  the  Kingdom  of  Bohemia 
for  1880,  by  Herr  J.  Seidl,  and  the  proc- 
ess has  been  condemned  for  very  similar 
reasons. 

Condition    of   Timber    at     Time    of 


77 

Preparation. — Getting  Hid  of  Moisture 
by  Stacking  or  Artificially. — The  hy- 
grometric  condition  of  timber  at  the 
time  of  injection  is  an  important  element 
in  the  success  of  the  operation,  all  im- 
portant with  the  Creosoting  process  es- 
pecially. Neglect  on  this  point  has  often 
been  the  cause  of  partial  or  total  fail- 
ure. Woody  fiber  in  itself  is  heavier 
than  water,  its  specific  gravity  being 
generally  considered  as  equal  to  1.5, 
water  being  1.0.  It  is,  therefore,  owing 
to  the  looseness  of  their  texture,  that  so 
many  kinds  of  timber  are  lighter  than 
water.  The  specific  gravity  of  fir  timber 
varies  ordinarily  between  0.5  and  0.8  ; 
the  difference  arising  as  often  from  the 
varying  density  of  the  timber  itself,  as 
from  the  quantity  of  water  contained. 
As  fir  timber  can,  under  certain  condi- 
tions, absorb  so  much  moisture  as  to  be- 
come water-logged,  or  actually  heavier 
than  water,  its  powers  of  absorption  can 
be  calculated  from  its  specific  gravity. 
It  can  take  up  as  much  as  from  60  to  150 
gallons  of  water  to  the  load  of  50  cubic 


78 


feet,  the  maximum  quantity  being,  of 
course,  an  exceptional  possibility.  Fir 
and  pine,  however,  frequently  contain  as 
much  as  from  15  per  cent,  to  20  per 
cent,  of  water,  after  from  two  to  three 
years'  stacking.  The  question  of  the 
pernicious  effects  of  an  excess  of  moisture 
in  the  timber  at  the  time  of  Creosoting, 
has  been  from  time  to  time  brought  be- 
fore this  Institution  by  Mr.  Bethell,  by 
Mr  Burt  and  by  the  author.  Large  logs 
taken  out  of  timber  ponds,  or  sleepers 
freshly  imported,  are  not  in  most  cases 
in  a  fit  condition  for  Creosoting  until 
after  having  been  stacked  for  from  four 
to  six  months.  The  author,  in  common 
with  most  of  the  earlier  operators  in 
this  process,  has  tried  various  methods 
for  artificially  drying  the  timber.  Steam, 
ordinary  and  super  heated,  currents  of 
hot  air,  and  drying  stoves  or  ovens,  have 
been  used  for  this  purpose,  but  have  all, 
in  this  country,  been  abandoned.  To 
subject  timber  to  a  dry  heat,  elevated 
enough  to  remove  its  moisture  with  the 
necessary  rapidity,  will  invariably  result 


79 


in  injury  to  the  wood.  Timber  piles 
stoved  before  Creosoting,  prove  brittle 
when  driven.  The  action  of  the  air- 
pump  in  the  ordinary  process  assists  the 
operation  by  withdrawing  air  from  the 
pores  of  the  wood  ;  but  it  is  a  mistake  to 
suppose  that  it  has  much  effect  in  with- 
drawing moisture. 

These  difficulties  have  perplexed  the 
author  for  many  years.  He  has  recently 
devised  a  method  by  which  to  get  rid  of 
the  moisture  as  part  of  the  timber-pre- 
serving process,  and  without  injury  to 
the  wood.  An  experiment  easy  to  repro- 
duce, and  which  explains  the  nature  of 
this  operation,  is  made  as  follows  :  An 
ordinary  glass  flask,  in  which  are  placed 
some  pieces  of  wood  saturated  with 
water  is  connected  by  glass  tubes  with 
an  experimental  air  pump.  By  working 
the  pump  the  air  is  extracted  from  the 
pores  of  the  timber,  but  however  effi- 
cient the  vacuum  may  be,  no  perceptible 
moisture  is  withdrawn,  nor  would  the 
water  be  removed  from  the  wood  except 
by  a  slow  evaporation  prolonged  beyond 


80 


practical  limits.  This  represents  the 
ordinary  action  of  the  air  pump  upon 
timber  in  a  Creosoting  cylinder.  If  suffi- 
cient heat  be  now  applied  beneath  the 
flask,  the  water  will  become  volatilized, 
and  will  be  withdrawn  rapidly  in  the 
shape  of  steam  by  the  action  of  the  air 
pump.  But  the  wood  will  be  found  to 
crack,  and  open  to  an  extent  which  is  not 
desirable.  This  illustrates  the  result  of 
applying  dry  heat. 

Now  take  a  similar  flask  with  a  con- 
densing apparatus  added  ;  moreover,  the 
flask  should  contain  Creosote  oil,  in 
which  the  wet  timber  is  submerged.  It 
must  be  constantly  borne  in  mind  that 
at  the  ordinary  tension  of  the  atmos- 
phere, the  boiling  point  of  the  Creosote 
oils  ranges  from  about  380°  Fahrenheit 
to  760°  Fahrenheit,  as  compared  to  water 
at  212°  Fahrenheit.  These  boiling  points 
are,  however,  lowered,  according  to  a 
well-known  law,  by  the  effects  of  a 
vacuum.  Let  the  Creosote  in  the  flask 
be  now  heated  to  212°  Fahrenheit,  whilst 
the  air  pump  is  put  into  operation.  The 


81 

heat  being  communicated  through  an  oily 
medium  will  not  injure  the  timber,  from 
which  the  water  is  volatilized,  and  drawn 
out  by  the  air  pump.  The  Creosote  oils 
are  not  volatilized,  as  the  temperature  is 
far  below  their  point  of  ebullition.  The 
water  is  speedily  and  effectually  removed, 
and  the  Creosote  takes  its  place. 

By  the  ordinary  and  well-known  proc- 
ess, after  the  timber  has  been  placed  in 
the  cylinder  and  the  air-tight  door 
closed,  the  air  is  exhausted  from  the 
cylinder,  the  Creosote  is  then  introduced 
heated  to  a  temperature  of  from  100° 
Fahrenheit  to  120°  Fahrenheit,  when  the 
air  pump  ceases  to  work,  and  the  press- 
ure pump  is  put  into  operation. 

Referring  now  to  the  new  process,  it 
will  be  seen  that  a  large  dome  is  placed 
on  the  top  of  the  cylinder,  to  which  the 
exhaust-pipe  of  the  air  pump  is  attached. 
The  exhausting  process  is  continued 
after  the  Creosote  has  been  introduced 
into  the  cylinder.  The  Creosote  during 
this  part  of  the  operation  should  not  be 
allowed  to  rise  quite  to  the  top  of  the 


82 


vessel,  a  free  space  being  preserved,  and 
the  dome  kept  empty,  so  that  the  Creo- 
sote is  not  drawn  through  the  exhaust 
pipe.     The  Creosote  is  raised  to  a  tem- 
perature a  little  exceeding  212°  Fahren- 
heit instead  of  120°  Fahrenheit  as  here- 
tofore.    The  exhausting  process  is  con- 
tinued until  all  the  water  is   extracted 
from  the  timber  in  the  form   of  vapor, 
drawn  through  the  dome,  condensed  by 
passing   through  the  worm  of  the  con- 
densing apparatus,  and  collected  in  the 
receiving  tank,  where   the   quantity  ex- 
tracted can  be  measured.     With  charges 
of  very  wet  sleepers,  the  author  has  suc- 
ceeded  in   withdrawing   water  equal  in 
volume  to  50  gallons  per  load  of  timber, 
and  replacing  this  water  with  an  equal 
volume  of  Creosote  by  the  action  of  the 
air  pump  alone.     If  necessary,  however, 
the  pressure  pump  can  be  afterwards  ap- 
plied in  the  usual  way. 

A  slight  additional  cost,  and  a  few 
hours'  additional  time  are  necessary  for 
dealing  with  very  wet  timber  by  this 
process  as  compared  with  the  ordinary 


83 

method.  But  the  expenditure  in  time 
and  money  is  not  so  great  as  would  be 
required  by  stoving  the  wood  before 
Creosoting.  If,  in  the  absence  of  arti- 
ficial methods,  timber  be  stacked  for  six 
months,  as  it  should  be,  the  interest  on 
capital  represents  a  certain  expenditure 
also.  The  author  ventures  to  suggest 
that  this  is  not  always  taken  sufficiently 
into  account,  in  giving  out  contracts  for 
creosoted  timber.  Other  conditions  be- 
ing equal,  dry  timber  is  at  a  disadvantage 
in  the  competition,  as  far  as  price  is  con- 
cerned, with  timber  just  landed.  Yet  a 
small  extra  expenditure  in  this  particular 
would  frequently  be  repaid  to  the  con- 
sumer twenty  or  thirty-fold  in  the  pro- 
longed duration  of  the  wood. 

Conclusion. — In  conclusion  the  author 
would  remark  that  with  regard  to  certain 
points  mentioned  in  this  paper,  upon 
which  some  controversy  has  at  times 
arisen,  he  has  been  careful  to  advance  no 
opinion  which  he  has  not  confirmed, 
either  by  the  opinions  and  investigations 
of  eminent  authorities,  or  by  careful  and 


84 

reiterated  experiments.  Many  hundreds 
of  experiments  have  been  in  fact  carried 
out  at  the  laboratories  of  the  author's 
firm  at  JSilvertown  during  the  last  five 
years,  with  the  especial  object  of  investi- 
gating the  properties  of  the  tar  oils  and 
other  antiseptics,  and  their  behavior  in 
contact  with  timber.  To  Mr.  Koyle,  Mr. 
Bendix,  and  Mr.  Holmes  of  the  chemical 
staff  of  his  Silvertown  Works  he  has  to 
return  his  best  thanks  for  their  skilled 
assistance,  and  particularly  to  Mr.  Ben- 
dix, who  has  been  more  especially  en- 
trusted with  the  conduct  of  these  experi- 
ments. To  Mr.  Gabbett  he  is  indebted 
for  the  drawings  exhibited. 

The  Treatment  of  Timber  by  Anti- 
septic Methods  has  been  acknowledged 
by  some  of  the  greatest  engineers  of 
this  country  to  have  been  useful  to  the 
art  of  constructive  engineering.  It  may 
be  made  even  more  useful  in  the  future 
than  it  has  been  in  the  past.  All  that 
the  advocates  for  its  still  more  extended 
development  can  desire  to  claim  will  be, 
that  their  methods  and  investigations 


85 


may  be  seriously  examined,  and  from 
time  to  time  decided  upon,  in  accordance 
with  the  results  which  science  and  ex- 
perience may  bring  to  light. 


DISCUSSION. 

Sir  Joseph  Bazalgette,  C.  B.,  President, 
said  the  subject  of  the  paper  was  an  ex- 
ceedingly practical  one.  Timber,  in  the 
majority  of  countries,  was  the  most  avail- 
able material  for  constructive  and  engin- 
eering purposes,  and  in  some  countries  it 
was  almost  the  only  material  which  could 
be  used.  The  great  defect  in  its  use  was 
its  want  of  durability.  Anything,  there- 
fore, which  could  remedy  that  defect,  and 
give  durability  to  the  timber,  must  be  a 
subject  of  great  interest  to  the  engineer. 
The  author  in  the  paper  had  given  the 
result  of  thirty-four  years'  experience, 
together  with  his  researches  into  what 
had  been  done  ages  before,  and  the  whole 
had  been  placed  before  the  members  in  a 
manner  showing  that  he  had  devoted  very 
great  ability  and  attention  to  the  subject. 


86 


Although  the  author  was  commercially 
engaged  in  that  branch  of  engineering, 
he  was  sure  the  members  would  feel  that 
the  paper  had  risen  considerably  above 
the  commercial  element,  and  had  clearly 
shown  that  science  could  be,  and  had 
been,  brought  to  bear  on  industrial  art, 
so  as  to  improve  it  and  make  it  of  great 
value. 

Mr.  Boulton  remarked  that  the  subject 
of  his  paper  was  one  which  had  occupied 
his  attention  for  many  years.  He  hoped 
he  had  clearly  explained  the  analytical  in- 
vestigations by  which  he  had  sought  for 
some  clue  to  what  was  a  rather  complex 
labyrinth,  namely,  the  kind  of  substance 
which  was  the  best  to  put  into  timber  for 
its  preservation.  He  had  employed  many 
of  those  substances,  and  the  conclusion 
at  which  he  had  arrived  was  that,  suppos- 
ing the  substance  to  be  a  good  antiseptic, 
whether,  as  in  former  times,  corrosive 
sublimate,  sulphate  of  copper,  or  chloride 
of  zinc  were  used,  or  whether  creosote 
oils,  there  was  always  a  close  connection 
between  the  durable  results  of  the  anti- 


87 


septic  and  the  immunity  of  that  antiseptic 
from  volatility  in  the  air  or  solubility  in 
water.  Timber  must  be  exposed  to  air 
for  engineering  purposes,  and  also  to 
water ;  in  some  cases  in  marine  work,  it 
was  in  the  water  altogether,  and  there- 
fore, the  antiseptic  ought  not  to  be  liable 
to  evaporation  or  to  being  washed  out 
by  the  action  of  the  water.  He  was  not 
there  to  advocate  the  use  of  the  creosote 
of  one  district  more  than  another,  because, 
commercially  speaking,  that  was  a  matter 
that  did  not  affect  him.  He  thought  that 
all  honest  creosotes  made  from  coal-tar  in 
England  were  useful  for  the  purpose  of 
preparing  timber;  but  he  thought  that 
some  of  them  were  more  useful  than 
others,  because  they  were  more  durable. 
If,  therefore,  engineers  would  take  the 
trouble  to  follow  out  his  idea,  and  study 
the  different  constituents  of  the  creosote 
oils,  remembering  which  of  them  were  the 
most  durable  and  the  least  soluble,  that 
would  give  a  clue  to  the  formation  of 
fresh  specifications  for  the  preparation  of 
timber.  He  did  not  think  that  the  pres- 


88 


ent  specifications  were  satisfactory  in  all 
respects.  Plate  6  represented  the  prod- 
ucts derived  from  Newcastle  coal,  such  as 
was  ordinarily  carbonized  in  London  gas- 
works. There  was,  as  had  been  explained 
in  the  paper,  a  different  series  of  products 
from  the  Midland  coals  ordinarily  car- 
bonized in  other  parts  of  the  country. 
Taking  the  same  coals — those  carbonized 
in  the  gasworks — and  subjecting  them 
by  carbonization  to  a  lower  temperature, 
another  class  of  products  would  be  ob- 
tained as  had  been  pointed  out  by  Dr. 
Armstrong  in  a  recent  discussion.  It 
was  as  well  that  engineers  should  bear 
that  in  mind,  as  they  were  now  witness- 
ing an  inauguration  of  a  new  series  of  in- 
dustries, namely,  the  partial  carbonization 
of  coal  in  coke  ovens,  partly  for  the  pur- 
pose of  getting  the  products  direct,  in- 
stead of  through  the  gasworks.  Those 
other  products  might  be  valuable,  but 
they  were  not  the  same  as  far  as  the 
preparation  of  timber  was  concerned,  for 
they  were  lighter  and  more  volatile.  He 
had  taken  the  trouble  to  get  some  truck- 


89 

loads  of  different  coals  used  ordinarily 
by  the  London  gas  companies ;  he  had 
carbonized  them  on  a  large  scale  at  lower 
temperatures,  and  had  found  that  he  ob- 
tained thinner  and  lighter  oils  with  a 
specific  gravity  of  from  930  to  1,030,  in- 
stead of  from  1,045  to  1,060,  and  he  had 
a  different  class  of  products  altogether. 

Dr.  C.  Meymott  Tidy  said  it  was  twenty 
years  ago  when  he  commenced  working 
with  creosote,  and  he  was  bound  to  admit 
that  since  that  time  his  views  had  under- 
gone considerable  changes ;  but  he  sup- 
posed there  was  no  great  harm  in  that, 
for  the  views  of  engineers,  politicians,  and 
even  of  theologians,  were  constantly  shift- 
ing. The  process  of  creosoting  was  of  a 
threefold  nature.  First,  there  was  the 
physiological  action  of  rendering  the 
wood  a  poison,  so  that  animals  could  not 
or  would  not  attack  it;  secondly,  there 
was  a  chemical  action,  consisting  chiefly 
in  the  coalgulation  of  the  albumen ;  and 
thirdly,  there  was  what  he  held  to  be 
by  far  the  most  important  action  of  the 
three,  namely,  the  simple  mechanical  ac- 


90 


tion.  The  process  of  creosoting  was  prac- 
tically a  choking  up  of  the  pores  of  the 
wood  so  that  neither  air,  moisture  nor  life 
could  get  inside.  He  well  remembered 
the  late  Dr.  Letheby  drawing  up  his  orig- 
inal specification.  No  doubt  he  was  very 
strong  in  his  belief  of  the  enormous  value 
of  carbolic  acid ;  indeed,  he  regarded  it, 
as  the  author  had  stated,  as  probably  the 
most  important  ingredient  of  the  tar.  In 
the  last  specification  which  he,  Dr.  Tidy, 
had  drawn  up  a  year  ago,  and  which  was 
now  being  employed  largely,  he  had 
laid  down  three  essentials,  and  as  they 
practically  represented  the  views  which 
he  held  on  the  subject  at  the  present  time, 
he  might  be  allowed  to  refer  to  them. 
The  first  point  of  the  specification  was 
that  the  creosote  should  be  completely 
liquid  at  a  temperature  of  100°  Fahren- 
heit, no  deposit  afterward  taking  place 
until  the  oil  registered  a  temperature  of 
93°.  That  point  was  considered  very 
fully.  The  temperature  at  which  creosot- 
ing was  performed  was  about  120°.  It 
did  not  appear  to  him  to  matter  one  iota 


91 


how  solid  the  creosote  was  (and  he  was 
bound  to  say  that  from  his  point  of  view 
the  more  solid  it  was  the  better),  so  long 
as  it  was  liquid  at  the  temperature  at 
which  the  creosoting  process  was  done. 
Seeing  that  the  process  was  carried  out 
at  a  temperature  of  120°,  he  thought  he 
was  right  in  specifying  that  the  creosote 
should  be  liquid  at  the  temperature  of 
100°.  The  next  point  was  (he  had  left 
out  a  specific-gravity  clause)  that,  tested 
by  a  certain  process,  the  creosote  should 
yield  a  total  of  8  per  cent,  of  tar  acids. 
He  was  aware  that  in  an  earlier  specifica- 
tion drawn  up  by  Sir  Frederick  Abel  and 
himself  about  three  years  ago.  they  speci- 
fied 10  per  cent.,  and  of  course  it  was 
only  fair  to  ask  him  why  he  had  thus  de- 
generated. Having  examined  a  very  large 
number  of  creosoted  timbers  that  had 
been  prepared  for  at  least  a  year,  he  was 
unable  to  detect  the  slightest  trace  of 
carbolic  acid  in  them.  This  fact  had  also 
been  very  prominently  and  excellently 
well  brought  out  by  Mr.  Greville  Wil- 
liams. But  although  after  a  short  period 


92 

there  was  no  trace,  so  far  as  he  could 
make  out,  of  carbolic  acid  in  the  sleeper, 
yet  the  wood  continued  as  sound  as  ever. 
It  was  also  a  fact  that  the  earlier  timbers 
were  creosoted  with  heavy  oils  containing 
only  a  small  quantity  of  carbolic  acid, 
nevertheless  these  very  sleepers  laid  the 
foundation  of  the  success  of  creosoting 
at  a  process.  Taking  those  two  facts  to- 
gether, it  appeared  to  him  that  they  had 
hitherto  placed  an  exaggerated  value  up- 
on the  carbolic  acid.  He  did  not  wish 
to  be  misunderstood.  He  did  not  say 
that  the  carbolic  acid  evaporated,  nor  that 
it  might  not  undergo  certain  chemical 
changes  in  the  wood;  he  did  not  know 
what  took  place,  and  that  was  not  the 
place  to  discuss  the  question.  It  was  on 
the  ground,  however,  he  had  mentioned, 
that  he  had  fixed  the  quantity  of  the  car- 
bolic acid  as  low  as  was  consistent  with 
obtaining  a  genuine  creosote.  In  other 
words,  he  fixed  8  per  cent,  not  because 
he  regarded  8  per  cent,  as  necessary  for 
the  purpose  of  creosoting,  but  because 
he  thought  from  a  large  number  of  an- 


93 


alyses  of  London  creosote,  that  by  fixing 
8  per  cent,  he  should  ensure  the  obtain- 
ing a  genuine  creosote.  In  the  other 
part  of  his  specification  he  admitted  that 
he  had  completely  altered  previous  speci- 
fications, namely,  in  requiring  that  the 
creosote  should  contain  at  least  25  per 
cent,  of  constituents  that  did  not  distil 
over  a  temperature  of  600°.  He  believed 
that  up  to  that  time  almost  every  specifi- 
cation had  required  that  the  oil  should 
contain  at  least  75  per  cent,  of  matters 
that  did  distil  over  600°.  He  entirely 
agreed  with  the  author  that  it  was  to  the 
heavier  oils  that  the  success  of  the  creo- 
soting  process  was  due,  and  it  was  there- 
fore by  the  amount  of  those  oils  that  did 
not  distil  over  at  a  temperature  of  600° 
that  the  excellence  of  the  creosote  to  be 
used  for  creosoting  purposes  should  be 
determined.  It  appeared  to  him  to  be 
highly  advisable  to  get  the  heaviest  creo- 
sotes for  the  work,  and  to  insist  upon  as 
great  a  quantity  as  possible  of  the  creo- 
sote being  driven  into  the  wood. 

Dr.  H.  E.  Armstrong  said  that,  on  the 


94 


whole,  he  concurred  in  the  views  expressed 
by  the  author.  He  thought  that  creosot- 
ing,  instead  of  being  an  operation  of  a 
threefold  character,  as  Dr.  Tidy  had 
stated,  was  of  a  onefold  nature.  Water 
had  to  be  excluded,  because  in  excluding 
water  everything  was  excluded  which  was 
likely  to  be  harmful.  When  water  was 
introduced,  other  things  were  introduced 
with  it,  especially  certain  organisms  which 
there  could  be  no  doubt  played  a  most 
important  part  in  effecting  the  rapid  de- 
cay of  timber.  He  agreed  with  Dr.  Tidy 
that,  mechanically,  it  was  of  great  import- 
ance to  choke  up  the  pores,  but  the  ob- 
ject was  not  so  much  to  choke  up  the 
pores  as  to  prevent  the  perpetual  moist- 
ening of  the  wood.  When  wood  was 
moistened,  and  was  subject  to  frequent 
variations  in  pressure,  it  necessarily  be- 
came after  a  time  reduced  to  a  very 
spongy  condition  mechanically,  and  its 
quality  was  in  that  way  materially  affected. 
If,  therefore,  the  access  of  moisture  could 
be  prevented  an  important  point  was 
gained.  The  author  had  briefly  referred 


95 


to  Pasteur's  experiments,  which  perhaps 
were  not  so  well  known  as  they  deserved 
to  be.  He  supposed  that  the  experiment 
to  which  special  reference  was  made  was 
that  conducted  with  sawdust.  M.  Pas- 
teur had  shown  that  if  ordinary  moist 
sawdust  had  air  passed  over  it  for  a  few 
hours,  there  was  obvious  evidence  of  de- 
cay afforded  by  the  production  of  car- 
bonic acid.  But  if  precautions  were  taken 
to  kill  all  the  organisms  attached  to  the 
sawdust  by  heating  it,  and  if  it  was  then 
moistened  with  water  deprived  of  organ- 
isms, and  exposed  to  a  current  of  air 
carefully  deprived  of  organisms  by  filter- 
ing through  cotton  wool,  the  current  of 
air  would  pass  over  it  for  hours  without 
there  being  any  evidence  of  the  decay  of 
the  wood.  That  was  the  fundamental  ex- 
periment upon  which  the  views  of  chem- 
ists with  regard  to  the  part  played  by 
organisms  were  based  at  the  present  day. 
With  reference  to  the  author's  remark  as 
to  the  difference  between  creosote,  prop- 
erly so-called,  and  coal-tar  oils,  he  thought 
there  was  a  little  misunderstanding  on 


96 


that  point.  The  author  stated,  "Creosote, 
correctly  so-called,  is  the  product  of  the 
destructive  distillation  of  wood,  and  coal- 
tar  does  not  contain  any  of  the  true  Creo- 
sote, which  has  never  been  used  for  tim- 
ber  preserving."      That   was   not   quite 
correct,  because  true  creosote  contained 
a  considerable  quantity  of  carbolic  acid 
and  cresylic  acid,  which  had  been  com- 
monly regarded  as  active  constituents  of 
ordinary  creosote  oil.     With  reference  to 
what  was  really  the  active  constituent  in 
.creosote  oils,  the  remarks  of  Dr.   Tidy 
met  with  his  approval  to  a  large  extent,  but 
he  should  be  inclined  to  predict  that  be- 
fore many  years  Dr.  Tidy  would  drop  his 
limit  from  8  per  cent,  to  6  per  cent.,  and 
perhaps  eventually  sink  it  altogether.    It 
was  very  much   to  be  hoped   that   that 
would  be  the  case,  because  he  thought 
that  engineers  were  using  a  material  for 
creosoting  that  ought  not  to  be  employed 
for  that  purpose,  and  probably  the  car- 
bolic acid  was  practically  of  very  little  use. 
He  did  not  think  that  the  coagulation  of 
the  albumenoids  to  which  reference  had 


97 


been  made,  took  place  to  any  large  extent, 
or  was  an  essential  part  of  the  process. 
That  was,  he  thought,  the  only  part  that 
could  be  assigned  to  the  carbolic  acid. 
There  could  be  very  little  doubt  that, 
within  a  comparatively  short  time,  either 
by  evaporation  or  by  being  dissolved  out, 
the  carbolic  acid  disappeared.  It  was  not 
there  in  any  form,  but  actually  went 
away.  There  was  no  probability  that  it 
would  be  fixed  in  such  a  way  as  to  escape 
attention  and  detection  by  the  tests  em- 
ployed by  Dr.  Tidy  and  Mr.  G.  Williams. 
He  was  inclined  to  think  the  action  was 
mainly  a  choking  action  as  described  by 
Dr.  Tidy,  the  access  of  water  to  the  wood 
being  prevented.  It  was  therefore  simply 
a  question  of  obtaining  an  oil  which  would 
do  that  in  the  best  possible  way,  which 
could  be  introduced  into  the  wood  with 
the  greatest  readiness,  and  would  remain 
in  it  under  ordinary  conditions,  for  the 
greatest  length  of  time ;  and  if,  as  the 
author  had  said,  with  the  oil  which  would 
exercise  that  action  engineers  could  in- 
troduce substances  like  acridine  and  other 


98 


compounds  of  a  poisonous  character,  so 
much  the  better. 

Professor  A.  Voelcker  remarked  that, 
as  had  been  pointed  out  by  the  author, 
the  antiseptic  treatment  of  timber  had 
almost  entirely  superseded  former  meth- 
ods, and  justly  so,  for  on  the  strength 
of  past  experience  there  could  be  no 
question  that,  when  properly  carried  out, 
the  impregnation  of  timber  with  crude 
creosote  was  the  most  efficacious,  the 
least  troublesome,  the  most  persistent, 
and  the  cheapest  process  that  could  be 
adopted.  He  gathered  from  the  paper 
that  the  author  was  rather  inclined  to 
think  that  chemists  had  attached  too 
much  importance  to  the  presence  of  car- 
bolic acid  in  creosote  oil.  He  had  point- 
ed out  that  certain  alkaloids  in  coal-tar 
possessed  antiseptic  properties,  even  in  a 
higher  degree  than  phenol,  and  had  sug- 
gested whether  it  would  not  be  desirable 
to  modify  somewhat  the  specifications  is- 
sued by  the  Crown  Agents  for  the  colo- 
nies, by  the  War  Office,  and  other  public 
bodies.  Professor  Yoelcker  agreed  that 


99 

the  heavy  tar-oils  were  extremely  useful, 
and  perhaps  more  so  than  the  light  tar- 
oils,  for  preserving  timber  intended  to  be 
used  for  railway  sleepers.  He  could  not 
go  so  far  as  Dr.  Tidy,  who  had  suggested 
(he  granted  somewhat  vaguely)  that 
chemists  had  attached  far  too  great  im- 
portance to  the  presence  of  carbolic  acid 
in  crude  creosote.  But  he  would  go  as 
far  as  to  say  that  for  preserving  well- 
seasoned  old  timber,  it  did  not,  perhaps, 
matter  so  much  whether  there  was  a  high 
percentage  of  carbolic  acid  in  the  creo- 
sote, as  it  mattered  that  there  should  be 
present  in  it  a  high  percentage  of  the 
oils  which  passed  over  on  distillation 
above  610°,  because,  as  Dr.  Tidy  had 
pointed  out,  the  effect  of  these  tar  com- 
pounds was  to  close  up  the  pores  of  the 
timber,  to  render  it  impervious  to  water, 
air,  and  other  debasing  influences ;  being 
at  the  same  time  in  itself,  comparatively 
speaking,  an  imperishable  substance,  like 
all  pitchy  products  when  completely 
dried.  But  it  should  be  borne  in  mind 
that  it  was'  requisite  not  only  to  preserve 


100 

well-seasoned  old  timber,  from  which  the 
moisture  was  expelled  almost  completely, 
but  that  of  late  years  a  great  deal  had 
been  done  in  preserving  telegraph-posts, 
gate-posts,  wooden  fencing,  hop-poles, 
and  the  like,  for  which  sapling-wood,  or 
at  any  rate  young  wood,  was  used. 
There  was  a  great  deal  of  difference  in 
the  chemical  constitution  of  the  two 
kinds  of  wood.  Sappling-wood  was  more 
or  less  filled  with  sap,  and  in  the  liquid 
which  circulated  in  it  there  were  perish- 
able substances  belonging  to  the  class  of 
albumenoids,  which  acted  as  ferments, 
and  caused  otherwise  imperishable  sub- 
stances to  decay.  The  primary  causes  of 
decay  of  greenwood  were  unquestionably 
the  albumenoid  substances ;  and  all  the 
older  processes,  such  as  the  corrosive 
sublimate,  or  kyanizing  plan,  or  the  im- 
pregnation with  other  metallic  salts, were 
based  on  the  principle  that  by  those  me- 
tallic salts,  notably  by  the  bichloride  of 
mercury  (corrosive  sublimate),  the  al- 
bumenoids were  precipitated,  and  ren- 
dered insoluble  and  incapable  of  acting 


101 

as  ferments.  In  green  wood  also,  the 
celluloise  was  in  a  more  tender  condition 
than  in  old  wood,  where  there  was  a 
larger  proportion  of  in  crusting  matter  ; 
there  was,  therefore,  a  greater  reason  for 
preventing  the  first  state  of  decomposi- 
tion ;  and  he  questioned  whether  creosote, 
which  was  sometimes  extremely  poor  in 
carbolic  acid,  was  the  proper  material  for 
preserving  wooden  structures  of  the  kind 
he  had  mentioned.  No  doubt  there  was 
a  good  deal  to  be  said  in  extenuation  of 
the  qualities  of  creosote,  for  the  process 
of  preserving  wood  in  open  tanks,  was 
sometimes  unskillfully — not  to  say  care- 
lessly— conducted ;  but,  making  all  allow- 
ance for  the  imperfections  of  the  meth- 
ods for  preserving  wooden  poles  in  that 
way,  there  could  be  no  doubt  that  some- 
times creosote  answered  remarkably  well, 
and  in  other  instances  the  same  process 
tended  to  make  the  wood  more  perishable 
than  it  would  have  been  had  it  not  been 
creosoted  at  all.  That  seemed  to  be  a 
contradiction,  but  according  to  the  evi- 
dence of  those  who  had  carried  on  the 


102 

process  with  more  or  less  success  for  fif- 
teen years  or  longer,  the  same  kind  of 
creosote  would  answer  extremely  well  for 
preserving  hard  timber  used  for  railway 
sleepers,  while  for  young  wood  it  did  not 
answer  the  purpose.  He  had  found,  from 
the  examination  of  samples  which  had 
been  sent  to  him,  that  there  were  great 
differences  in  the  composition  of  different 
creosotes.  Not  long  ago  he  had  received 
a  sample  which  yielded,  on  distillation 
from  the  boiling  point  up  to  610°,  only 
39  per  cent,  of  distillate,  containing  no 
more  than  3  per  cent,  of  carbolic  acid ; 
while  another  sample  yielded  14f  per  cent, 
of  a  watery  liquid  with  a  little  light  oil, 
the  water  being  strongly  ammoniacal ; 
and  it  was  well  known  that  any  ammoni- 
acal water  left  in  the  creosote  was  extreme- 
ly injurious  to  the  timber.  The  same 
sample  only  yielded  47£  per  cent,  of  dis- 
tillate; including  4£  per  cent,  of  crude 
carbolic  acid.  In  a  third  sample  he  found 
only  5  per  cent,  of  carbolic  acid.  He 
ventured  to  think  that  creosote  contain- 
ing as  little  as  5  per  cent,  of  crude  car- 


103 

bolic  acid  was  not  a  good  liquid  for  pre- 
serving immature  wood,  simply  because 
it  was  not  strong  enough  to  precipitate 
or  render  ineffective  albumenoid  sub- 
stances. Even  Dr.  Tidy,  in  the  recent 
modifications  of  his  views,  still  recom- 
mended that  the  creosoting  liquid  should 
contain  as  much  as  8  per  cent,  of  crude 
carbolic  acid.  A  great  deal  had  been  said 
about  the  specific  gravity  of  the  creosote. 
He  confessed  that  he  did  not  attach  very 
great  importance  to  specific  gravity,  but 
he  did  attach  great  importance  to  the 
presence  of  a  fair  percentage  of  phenol, 
or  crude  carbolic  acid,  if  it  was  wished  to 
preserve  green  wood,  such  as  that  used 
for  telegraph  posts  or  hop -poles ;  because 
it  was  essential  that  the  first  tendency  to 
subsequent  decay  should  be  counteract- 
ed, and  that  could  not  be  done  without 
the  introduction  of  a  sufficient  quantity  of 
carbolic  acid.  In  the  case  of  hard  timber 
the  main  object  was  to  fill  up  the  pores. 
There  was  not  so  much  albumenoid  matter 
present,  and  the  timber  would  keep  fairly 
well  if  moisture  was  excluded ;  that  was 


104 

effected  by  heavy  tar  oil  which  filled  up  the 
pores,  and  rendered  the  wood  very  hard, 
so  that  there  was  not  the  same  necessity 
for  the  presence  of  carbolic  acid.  He 
could  even  understand  that  if  crude  creo- 
sote contained  a  very  small  quantity  of 
carbolic  acid,  as  in  the  case  he  had  men- 
tioned, and  if  there  should  be  a  large 
proportion  of  the  more  solid  constituents 
of  creosote,  the  pores  externally  at  any 
rate  would  be  closed  up,  and  the  same 
thing  would  take  place  by  painting  or 
pitching  unseasoned  wood  ;  the  solid  con- 
stituents closed  up  the  pores  of  the  outer 
layers,  introducing  nothing  to  render  the 
albumenoids  ineffective  as  a  ferment,  so 
that  the  moisture  was  kept  in,  and  in  that 
way  decay  was  actually  hastened, whereas 
if  free  passage  were  allowed,  the  wood 
would  be  washed  out  and  would  keep 
longer.  Engineers  knew  from  experience 
that  green  wood,  when  thoroughly  paint- 
ed or  pitched,  decayed  more  rapidly  than 
wood  in  its  natural  state.  In  order  that 
the  point  might  be  settled  he  would  sug- 
gest that  some  experiments  be  tried  with 


105 

creosote  containing  various  proportions 
of  carbolic  acid,  not  with  reference  to  the 
preservation  of  railway  sleepers,  but  of 
younger  wood.  Strictly  comparative  ex- 
periments should  be  made  with  crude 
creosote,  one  sample  containing  5  per 
cent.,  another  10  percent.,  and  a  third  15 
per  cent,  that  being  the  usual  range  of 
carbolic  acid  in  commercial  creosote. 
Some  well-conducted  experiments  in  open 
tanks  with  creosote  of  various  strengths 
would,  he  thought,  finally  settle  the  ques- 
tion. He  could  not  help  thinking  that 
it  would  be  requisite  for  the  proper  car- 
rying out  of  the  process  that  there  should 
be  something  like  10  per  cent,  of  crude 
carbolic  acid  in  the  creosoting  liquid ;  at 
any  rate,  without  further  information  on 
the  subject,  he  should  be  disindined  to 
recommend  anybody  wishing  to  preserve 
hop-poles  or  telegraph  posts  to  use  any 
liquid  containing  a  less  amount  than  he 
had  mentioned. 

Mr.  H.  K.  Bamber  said  it  appeared  to 
him  that  the  whole  secret  of  the  paper 
was  to  be  found  in  the  paragraph,  "  By 


106 

the  light  of  the  evidence  now  accumu- 
lated, it  may  be  advisable  to  review  the 
question  as  to  the  relative  value  of  these 
various  bodies  contained  in  the  heavy  oils 
as  regards  the  preservation  of  timber. 
Some  of  them  are  becoming  valuable  for 
other  purposes.  Which  of  them  should 
the  engineer  retain  for  injecting  wood  ?  " 
Carbolic  acid,  if  left  in  creosote,  was 
worth  2d.  a  gallon,  and  if  taken  out  from 
4s.  to  40s.  per  gallon,  according  to  the 
state  of  purity.  The  author's  idea  ap- 
peared to  be  that  nothing  should  be  left 
in  the  creosote  which  it  would  pay  him 
better  to  take  out  >  in  fact,  there  should 
be  nothing  left  that  was  worth  more  than 
the  proverbial  2d.  He  did  not  appear  to 
see  the  difference  in  our  color  between 
the  two  pennies  and  the  two  sovereigns. 
The  difference  in  the  town-made  tar  and 
the  country  tar  did  not  arise  so  much 
from  the  difference  of  coal  used  as  from 
the  degree  of  heat  used  in  making  the 
gas.  In  London  it  was  desired  to  obtain 
a  harder  coke  that  would  do  for  engines, 
.and  for  that  purpose  a  much  higher 


107 

temperature  was  used,  and  the  most  lumi- 
nous portion  of  the  gas  fiist  formed  was- 
decomposed  on  coming  into  contact  with 
the  sides  of  the  red-hot  retort,  the  result 
being  gas  charcoal,  naphthaline,  and  a 
gas  of  less  illuminating  power.  With  re- 
gard to  Dr.  Letheby's  specification,  that 
very  specification  was  advocated  and  rec- 
ornmended'by  Messrs.  Burt  and  Boulton, 
but  then  carbolic  acid  had  not  become  so- 
valuable  when  separated.  Now  the  speci- 
fication recommended  was  drawn  up  by 
Dr.  Tidy,  and  if  the  author  could  get  his- 
views  adopted  there  would  soon  be  a  very 
tidy  specification  to  work  from.  The  au- 
thor had  mentioned  some  experiments  of 
Dr.  Tidy's  with  naphthaline  injected  into 
wood,  but  he  had  given  no  facts  or  data,, 
merely  expressing  his  own  opinion. 
Again,  the  experiment  was  not  similar  to 
the  exposure  of  creosoted  sleepers,  which 
were  not  subjected  to  a  temperature  of 
150°  Fahrenheit  in  a  closed  vessel.  He 
would  give  the  results  of  two  experiments- 
that  he  had  made  in  1882,  one  with  coun- 
try oil,  condemned  by  the  author,  and 


108 

one  with  Mr.  Boulton's  own  oil,  full  of 
naphthaline.  He  took  a  piece  of  wood 
(deal),  3  inches  by  3  inches  by  8  inches, 
and  dried  at  230°  Fahrenheit,  until  it  lost 
no  more  weight,  so  that  there  was  no 
water  left  in  it  to  cause  loss.  He  then 
kept  it  in  a  vessel  containing  the  author's 
London  creosote,  heated  to  180°  Fahren- 
heit, having  a  weight  on  the  wood  to  keep 
it  under  the  creosote.  It  took  up  1,020 
grains,  after  being  wiped  from  excess  of 
creosote  outside.  It  was  then,  on  Feb- 
ruary 7th,  1882,  placed  on  a  mantelshelf, 
where  the  temperature  was  never  above 
70°  Fahrenheit,  and  generally  between 
40°  and  50°.  It  was  repeatedly  weighed, 
and  the  loss  was  constant  until  June  5th, 
1882,  when  it  had  lost  487  grains,  equal 
to  47.75  per  cent,  of  the  creosote  put  in. 
Now,  as  there  were  only  10  per  cent,  of 
crude  tar  acids  in  the  creosote,  what  was 
it  that  made  up  the  47.75  per  cent,  loss? 
Water  there  was  none.  The  loss  arose 
chiefly  from  evaporation  of  the  naphtha- 
line. At  the  same  time  he  treated  a  simi- 
lar piece  of  wood,  3  inches  by  3  inches 


109 

by  6  inches — 2  inches  shorter — dried  at 
the  same  temperature,  until  it  ceased  to 
lose  weight.  It  was  then  immersed  in 
country  oil,  specific  gravity  1,045,  and 
kept  under  the  oil  by  a  weight,  but  with- 
out applying  heat.  It  absorbed  1.788 
grains  of  the  creosote,  so  that  the  wood, 
which  was  a  quarter  smaller,  took  up, 
actually,  in  cold,  more  than  double  the 
quantity  that  the  other  piece  did  of  the 
author's  oil  at  180°  Fahrenheit.  The 
piece  was  placed  side  by  side  with  the 
other  on  the  mantelshelf,  and  in  four 
months  it  had  lost  575  grains,  or  42.33 
per  cent,  of  the  oil  taken  up.  But  that 
was  not  fair  to  the  second  piece  of  wood, 
for  it  was  so  saturated  that  some  of  the 
oil  drained  out  on  the  mantelshelf,  and 
of  course  contributed  to  the  loss  of 
weight,  although  it  was  not  by  evapora- 
tion. The  oil  contained  about  20  per 
cent,  crude  tar  acids.  Those  were  plain 
facts,  and  showed  that  the  author's 
contention  "that  country  oils  are  not 
good  for  creosoting  timber  because  of 
their  instability"  was  contrary  to  fact. 


110 

The  beautiful  white  substance,  naphtha- 
line, was  liable  to  sudden  changes.  It 
might  at  one  moment  be  a  black  dirty- 
looking  substance,  and,  by  the  applica- 
tion of  a  moderate  heat,  it  became  volatil- 
ized and  condensed  into  a  lustrous  sub- 
stance. The  author,  by  Dr.  Tidy's 
experiments,  had  tried  to  make  out  that 
it  was  not  volatile.  Camphor,  although 
it  could  not  be  volatilized  by  heat  with- 
out decomposition,  yet  it  was  well  known 
that  a  piece  of  camphor,  even  when 
wrapped  in  paper  or  any  porous  mate- 
rial, would  soon  pass  away  by  evapora- 
tion ;  and  it  was  so  with  the  naphtha- 
line. Many  attempts  had  been  made  to 
prepare  tar  colors,  &c.,  from  naphthaline, 
but  as  yet  without  success ;  it  was  worth 
nothing  (except  in  small  quantities  in  the 
albo-carbon  gas-burners)  when  separated 
from  the  creosote ;  and  that  was  the  rea- 
son why  it  was  so  valuable,  according  to 
the  author,  in  the  creosote.  But  if  ever, 
by  chemical  research,  naphthaline  became 
as  valuable  as  carbolic  acid,  it  would  then 
become  so  volatile  as  to  escape  from  the 


Ill 

creosote  altogether,  and  chemists  would 
be  asked  to  reconsider  their  creosoting 
specifications.  As  to  the  solubility  of  car- 
bolic acid  in  water  and  alkaline  solutions, 
which  the  author  said  was  a  disadvantage, 
he  maintained  that  it  was  an  advantage, 
for  it  enabled  the  acid  gradually  to  dis- 
solve in  the  water  and  sap,  and  thus  get 
into  the  substance  of  the  wood  and  pre~ 
vent  decay,  while  the  other  portion  of 
the  creosote  remained  like  beauty,  only 
skin-deep.  To  say  that  because  carbolic 
acid  could  not  be  found  in  creosoted 
sleepers  after  twenty  or  thirty  years,  and 
that  therefore  it  had  nothing  to  do  with 
stopping  decay,  was  absurd.  It  might 
as  well  be  said  that  a  few  days  after  a 
large  fire  only  one  or  two  policemen  were 
found  and  no  fire-engines,  and  that  there- 
fore the  policemen  put  out  the  fire  and 
not  the  engines.  Carbolic  acid  was  an 
oxidizable  substance,  and  would  protect 
the  wood  from  oxidation  or  decay.  It 
instantly  prevented  decomposition,  and 
destroyed  the  life  of  the  germs  which 
caused  decay,  being  also  poisonous  to 


112 

most  insects.  Dr.  Tidy  had  mentioned 
the  number  of  analyses  he  had  made, 
and  how  long  his  experience  had  lasted. 
Mr.  Bamber  might  therefore  be  allowed 
to  state  that  he  had  tested  samples  of 
creosote  for  the  last  twenty-five  years, 
and  had  practical  experience  in  the  proc- 
ess of  creosoting.  It  was  his  opinion 
that  to  creosote  timber  properly  the 
creosote  tank  must  not  be  only  the 
"  waste  tub "  for  distilling  works.  It 
was  easy  to  get  good  country  oil  with  18 
to  25  per  cent,  crude  tar  acids,  yielding 
no  deposit  of  that  volatile  substance, 
naphthaline.  He  had  met  with  some 
samples  of  so-called  creosote  that  con- 
tained nearly  half  their  bulk  of  filth,  con- 
sisting of  charred  oil,  &c.,  he  presumed 
the  residues  from  anthracene  manufac- 
ture, yet  when  the  creosote  was  rejected 
every  effort  was  made  to  induce  the  be- 
lief that  it  was  some  of  the  best  creo- 
sote. 

Dr.  Albert  J.  Berneys  said  that  no  one 
could  doubt  the  conclusion  that  the  sub- 
stances preferred  should  be  germ  ex- 


113 

cinders  as  well  as  germicides,  and  those 
contained  in  the  oils  which  were  heavier 
than  water.  His  contention  would  be  to 
retain,  at  least  in  part,  and  to  the  extent 
of  2  per  cent.,  the  carbolic  acid  as  well 
as  the  naphthaline  and  the  alkaloids. 
The  arguments  in  favor  of  carbolic  acid 
were  very  strong.  Where  the  creosoted 
timber  was  covered  up  in  the  ground  the 
solubility  in  water  assisted  in  diffusing  it 
somewhat  in  the  earth,  and  thus  extended 
its  sphere  of  action.  Nor  should  that 
solubility  be  exaggerated.  In  a  dry  soil 
the  loss  could  only  be  by  heat,  and  that 
would  also  affect  other  ingredients.  It 
said  much  for  the  durability  of  carbolic 
acid  that,  in  spite  of  the  employment  of 
heavier  types  of  tar-creosote  in  early 
days,  it  was  distinctly  present  in  many 
cases  recorded  in  the  experiments  of  Mr. 
Greville  Williams.  In  one  specimen 
wood  creosoted  thirty  years,  distilled 
with  water,  a  distinct  reaction  of  phenol 
was  obtained  in  a  case  where  most  of  the 
oil  and  all  the  naphthaline  had  disap- 
peared. In  another,  creosoted  thirty-two 


114 

years,  the  phenol  reaction  was  very 
distinct.  In  a  third,  creosoted  twenty- 
nine  years,  the  phenol  reaction  was  very 
strong  when  distilled  with  acid,  but  was 
also  distinctly  present  in  a  free  state  ; 
whereas  there  was  no  naphthaline  and 
very  little  oil.  In  cases  where  no  free 
phenol  was  found,  it  was  discoverable  in 
combination.  The  power  possessed  by 
phenol  for  coagulating  albumen  could 
not  be  exaggerated.  He  would  not  de- 
scribe his  own  experiments  ;  but  in  his 
hospital  work  he  was  very  familiar  with 
the  high  antiseptic  power  of  carbolic 
acid.  The  experiments  of  Mr.  Greville 
Williams  with  the  white  and  yolk  of  an 
egg  only  showed  that  the  alkaloids  of 
the  tar-creosote,  weight  for  weight,  were 
equal  to  the  carbolic  acid  as  germicides, 
but  certainly  no  more;  and  that  the 
.__i_th  part  of  phenol  bore  no  relation 
to  the  amount  of  albumen  present.  If 
all  the  albumen  had  been  coagulated  it 
would  not  have  putrefied.  For  Mr. 
Williams  further  stated  that  1  per  cent, 
of  phenol  and  1  per  cent,  of  alkaloidals 


115 

were  of  equal  value.  He  believed  in  the 
coagulation  theory  by  phenol  of  the 
albumen  of  the  wood,  but  unless  enough 
was  used  it  was  as  with  disinfectants.  If 
he  had  a  quantify  of  hydrogen  sulphide 
in  the  air  of  a  room,  and  he  only  used 
enough  chlorine  to  unite  with  one-half  of 
the  hydrogen  present,  where  would  the 
disinfection  be?  It  was  the  worst  of 
disinfectants  that  generally  they  could 
not  be  used  in  sufficient  quantities.  The 
benefit  of  them  was  (as  Miss  Nightin- 
gale had  said)  that  it  was  necessary  to 
open  the  window  when  they  were  used. 
It  was  the  same  with  phenol.  If  he  did 
not  coagulate  the  albumen,  of  which 
there  was  but  little  in  the  wood,  he 
failed.  But  the  phenol  had  the  property 
and  the  additional  advantage  of  volatil- 
ity. It  took  a  long  time  for  even  the 
free  phenol  to  evaporate,  so  much  was  it 
protected  and  shut  up  by  the  oil  and 
naphthaline  in  the  tar-creosote.  And  he 
believed  that  not  only  was  carbolic  acid 
more  potent  as  an  antiseptic  than  any 
other  constituent  of  the  tar-creosote,  but 


116 

that  it  was  present  in  larger  quantities 
than  the  alkaloids  which,  according  to 
Mr.  Williams,  were  equal  to  it  weight  for 
weight. 

Mr.  W.  Foster  regarded  the  question 
brought  forward  by  the  author,  as  to  the 
value  of  alkaloidal  substances,  as  a  very 
important  one.  In  a  paper  which  he  had 
recently  read  before  the  Institution,  he 
had  remarked  on  the  possibility  of  some 
of  the  nitrogen,  which  he  was  then  in 
search  of,  being  in  tar  in  the  condition  of 
alkalodial  bodies.  The  author  had  men- 
tioned five  or  six  of  those  nitrogenous 
bodies,  and  there  were  probably  others. 
The  recent  investigations  of  chemists 
had  shown  that  pitch  itself  contained  an 
appreciable  amount  of  nitrogen.  Acridine, 
of  which  an  example  had  been  given  in 
the  table,  contained  the  lowest  percent- 
age of  nitrogen,  and  had  the  highest 
boiling-point.  Having  regard  to  the 
pitch,  it  was  possible  that  there  were 
other  nitrogenous  bodies  which  had  a 
still  higher  boiling-point,  and  a  lower 
percentage  of  nitrogen  than  in  the  case 


117 

of  acridine.  The  quantity  of  those 
alkaloidal  substances  in  the  tar  was  very 
small.  There  was  no  information  as  to 
their  relative  proportions ;  and  as  the 
percentage  of  nitrogen  varied  from  17.7 
to  7.8,  it  would  not  be  wise  to  specify 
how  much  of  those  bodies  was  present  in 
the  tar.  He  thought  he  might  say  that 
there  was  not  more  than  from  3  to  4  per 
cent.  If,  therefore,  they  had  any  value 
in  the  preservation  of  wood,  their  effect 
must  be  very  powerful.  He  was  inclined 
to  look  at  the  question  of  the  preserva- 
tion of  wood  by  the  aid  of  some  facts 
which  were  a  little  outside  the  subject. 
He  might  be  pardoned  for  referring  to 
the  corrosion  of  iron.  Iron  could  remain 
permanent  in  dry  oxygen,  in  pure  water, 
or  in  pure  carbonic  acid  gas  ;  in  any  two 
of  those  it  remained  permanent ;  it  was 
only  by  the  conjoint  influence  of  the 
three  that  corrosion  was  effected.  Pitch, 
he  believed,  was  the  best  preservative  of 
iron  that  was  to  be  had,  and  if  applied  to 
a  clean  surface  free  from  oxide  (rust),  it 
was  impossible  to  say  when  the  surface 


118 

of  pitch  would  fail  to  protect  the  iron. 
He  was  of  course  speaking  of  the  con- 
tinuity of  surface  being  preserved.  Pitch 
was  a  substance  of  a  most  permanent 
character,  being  almost  destitute  of  any 
chemical  attributes  ;  if,  therefore,  the  cel- 
lular structure  of  the  wood  could  be 
thoroughly  permeated  by  it,  as  long  as 
the  continuity  was  perfect,  it  would  be 
preserved.  Of  course,  that  could  never 
be  fully  realized  in  practice.  In  the  case 
of  green  wood,  the  question  arose  as  to 
the  coagulation  of  albuminous  matter. 
No  need  to  go  far  afield  to  get  plenty  of 
instances  showing  that  if  water  and  im- 
pure air  could  be  kept  out,  the  preserva- 
tion would  be  prolonged.  The  author 
had  referred  to  the  experiments  of  Petti- 
grew  ;  but  the  inference  he  had  drawn 
was  not  the  only  one.  If  albuminous 
matter  was  dried,  it  could  be  kept  as  a 
horny  substance  for  an  indefinite  length 
of  time.  A  piece  of  glue  could  be  pre- 
served intact  in  the  same  way.  If  white 
of  egg  or  glue  were  moistened  and  ex- 
posed for  a  certain  time,  it  putrefied. 


119 

The  inferences  deducible  from  Petti- 
grew's  experiments  could,  he  thought,  be 
traced  to  the  removal  of  water  from  the 
muscle  (the  heart),  which  had  been  the 
subject  of  the  experiments.  The  whole 
thing  might  be  summed  up  in  the  grave- 
digger's  reply  to  Hamlet,  "Water  is  a 
sore  destroyer  of  the  dead  body." 

Mr.  W.  Carruthers  thought  that  the 
botanical  aspect  of  the  question  should 
be  at  the  basis  of  the  inquiry ;  for  with- 
out a  proper  appreciation  of  the  circum- 
stances under  which  vegetable  tissues 
were  destroyed,  it  was  impossible  rightly 
to  appreciate  the  means  by  which  that 
destruction  could  be  prevented.  While 
he  agreed  with  much  that  had  been  said, 
he  felt  bound  to  differ  from  a  great  deal 
that  he  had  heard.  He  acknowledged 
the  great  importance  of  pitch  for  preserv- 
ing the  external  surface  of  wood.  But 
wood  decayed  not  only  from  chemical 
agents,  air  and  water ;  but  much  more 
from  the  action  of  parasites.  He  could 
easily  see  that  if  a  body  was  entirely  pro- 
tected externally  by  pitch,  it  would  be 


120 

preserved  from  chemical  changes,  but  not 
from  the  more  injurious  and  dangerous 
attacks  of  fungal  parasites.  They  were 
developed  from  spores,  and  the  attack 
might  be  made  through  a  flaw  or  crack  in 
the  wood.  When  the  wood  was  exposed 
to  the  desiccation  of  the  air,  flaws  con- 
tinually appeared,  and  wherever  a  spore 
could  get  access,  there  would  begin  de- 
velopment of  the  mycelium  or  root  of  the 
fungus,  which  penetrated  the  wood  wher- 
ever nutritious  materials  were  supplied 
through  its  whole  course  ;  so  that  unless 
the  wood  was  preserved  by  some  sub- 
stance which  would  prevent  the  life  of 
fungi,  its  destruction  was  certain.  He 
exhibited  a  specimen  of  wood  the  date  of 
the  creosoting  of  which  was  not  known, 
but  it  had  been  used  in  a  hurdle  for  at 
least  ten  years.  The  lower  creosoted  por- 
tion, embedded  in  the  earth,  did  not  show 
the  slightest  injury ;  but  the  upper  part, 
exposed  to  the  air,  and  cracked,  had  been 
attacked  from  the  outside  by  minute  veg- 
etation. Some  of  the  spores  had  obtained 
access  to  the  interior,  which  had  not  been 


121 

antiseptically  preserved,  the  fungi  had 
enormously  developed,  and  the  interior 
had  been  destroyed  by  them.  The  same 
thing  had  occurred  in  the  case  of  two 
specimens  of  telegraph  poles.  The  ex- 
terior of  the  specimen  which  he  exhibited 
had  been  fairly  preserved,  but  the  interior 
had  been  destroyed.  It  was  remarkable 
that  the  interior  was  colored  by  the  in- 
jection of  what  he  supposed  he  must  call 
creosote ;  but  it  had  not  been  sufficient  to 
serve  as  an  antiseptic,  as  it  had  permitted 
the  free  growth  of  fungi,  which  ramified 
through  the  base  of  the  pole  and  com- 
pletely destroyed  the  cellulose  or  lignine, 
leaving  it  a  fragile  skeleton.  It  appeared 
to  him  that  what  was  needed  was  a  suffi- 
cient impregnation  of  the  wood  with  creo- 
sote, and  with  that  element  in  it  which 
was  destructive  to  vegetable  life.  He  did 
not  know  from  experiments  what  that 
element  was,  but  he  did  know  that  there 
was  an  element  in  crude  creosote  that 
was  extremely  destructive  to  vegetable 
life,  viz.,  carbolic  acid.  Not,  however,  in 
all  strengths,  for  Koch,  a  distinguished 


122 

German  mycologist,  had  found  that  certain 
liquids,  with  5  per  cent,  of  carbolic  acid, 
would  support  fungi;  so  that  the  pres- 
ence of  a  small  percentage  was  not  de- 
structive to  vegetable  life.  That  was  ex- 
tremely important  in  relation  to  the  ob- 
servations of  Prof.  Voelcker.  Another 
specimen  from  a  telegraph  pole  had  been 
completely  destroyed  by  a  fungus  (He- 
ticularia).  There  was  on  one  side  a 
yellowish  dust,  consisting  entirely  of  the 
spores  of  the  plant.  But  in  a  specimen 
from  a  hurdle,  which  had  been  in  use 
since  1861,  when  it  was  creosoted,  the  ex- 
terior, although  it  had  no  coating  of  tar, 
still  exhibited  the  minutest  marks  of  the 
tools  employed  upon  it,  and  the  interior, 
which  was  completely  saturated  with  a 
brown  substance,  was  as  good  and  fresh 
as  if  it  had  been  creosoted  yesterday, 
without  a  particle  of  fungus.  There  was 
a  little  greenish  vegetation  on  the  outside, 
but  it  was  epiphytic,  and  not  injurious  to 
the  wood ;  there  was  no  fungal  vegeta- 
tion whatever.  The  wood  had  been  enor- 
mously increased  in  weight,  and  he  had 


123 

ascertained  microscopically  that  there 
was  no  deposit  in  the  interior  of  the  cells. 
The  whole  of  the  lignine  and  of  the  sec- 
ondary deposits  had  been  colored  by  that 
material,  so  that  the  tissue  had  been  com- 
pletely altered.  It  appeared  to  him  that 
there  had  been  a  new  combination  through 
the  injected  material,  producing  an  an- 
tiseptic condition  of  the  wood  which  was 
fatal  to  the  fungi.  There  was  a  little 
free  carbolic  acid  crystallizing  in  the  in- 
terior of  the  cells,  but  it  did  not  seem  to 
him  that  that  was  the  explanation  of  it. 
He  should  be  glad  if  those  who  were  con- 
versant with  the  chemical  aspect  of  the 
subject,  would  inquire  into  the  real  na- 
ture of  the  change  which  had  produced 
the  discolored  and  altered  condition  of 
the  lignine.  In  his  opinion  nothing  had 
been  introduced  for  preserving  timber 
that  could  compare  with  the  creosote 
used  in  the  specimen  he  had  exhibited, 
which  had  been  exposed  to  the  air  nearly 
twenty  years,  and  yet  the  ragged  edges 
of  the  chips  on  the  outside  had  not  even 


124 

been   touched  by  atmospheric   or  other 
destructive  agents. 

Mr.  Henry  Maudslay  observed  that,  in 
the  case  of  Old  London  Bridge,  the  decay 
of  the  timber  piles  of  the  piers  varied  ac- 
cording as  they  were  constantly  under 
water,  or  exposed  to  water,  air,  and  sun ; 
or  exposed  especially  to  salt  water  or  to 
fresh  water  on  the  rise  and  fall  of  the 
tide.  There  were  many  combinations  of 
circumstances  that  tended  practically  to 
destroy  timber,  and  it  was  therefore  most 
desirable  to  ascertain  the  exact  position 
that  would  be  occupied  by  a  solid  pile 
driven  into  the  earth  to  support  a  struc- 
ure — whether  it  was  to  be  exposed  to  the 
constant  action  of  the  water  below  in  the 
earth,  or  to  a  change  in  the  rise  and  fall 
of  the  tide,  or  to  the  influence  of  moisture 
gradually  attacking  it  above  the  highest 
spring-tide  level.  On  the  Arran  and 
Snowdon  mountains  he  had  been  lately 
excavating  soil  in  order  to  form  a  reser- 
voir, and  had  come  across  some  of  the 
largest  roots  of  red  pine  timber  that  he 
had  seen  in  that  locality.  There  were  no 


125 

trees  on  the  mountains  at  the  present 
time,  and  it  must  have  taken  many  years 
for  the  timber  to  have  grown  at  that  ele- 
vation— 1,200  to  1,500  feet  above  the  level 
of  the  sea.  The  timber  was  of  a  mag- 
nificent character ;  these  roots  had  been 
submerged  perhaps  centuries.  The  roots 
had  been  found  in  situ  covered  with  a 
layer  of  disintegrated  earth  saturated  with 
water  from  the  copper  mines.  They  had 
been  preserved  in  that  way  by  nature, 
but  now  that  they  were  being  exposed  to 
the  air,  they  were  in  some  cases  begin- 
nin  to  crumble  away.  The  props  and 
supports  in  old  workings  of  copper  mines 
were  preserved,  and  would  burn  with 
great  difficulty.  Since  the  Royal  George 
had  sunk  in  1782,  all  the  timber  had  be- 
come saturated  with  sea-water,  which  was 
so  destructive  to  the  cast-iron  cannon, 
that  they  were  made  as  soft  as  plumbago ; 
but  salt  water  had  a  great  effect  upon  the 
preservation  of  the  oak  wood,  making  it 
quite  green.  The  timber  was  so  hardened 
that  all  the  pores  seemed  to  have  been 
filled  with  some  material  that  was  suit- 


126 

able  to  its  preservation.  It  still  retained 
that  quality,  as  shown  in  the  case  of  a 
billiard  table  made  for  Her  Majesty,  and 
by  another  now  in  his  late  father's  house 
at  Norwood.  This  table  had  been  made 
by  Thurston  in  1860,  from  the  wreck  which 
was  raised  in  1841.  With  regard  to  the 
decay  of  iron,  he  might  be  permitted  to 
mention  that  Queen  Anne's  statue  at  St. 
Paul's  cathedral,  was  one  of  the  finest  of 
London  specimens  of  decay  of  iron  that 
engineers  could  examine.  It  consisted  of 
cast  iron,  wrought  iron,  lead,  and  stone, 
all  of  which  were  mouldering  away  by  the 
action  of  nature,  the  character  of  the  air, 
and  the  water.  The  whole  of  the  iron 
work  was  a  magnificent  specimen  of  age 
and  deterioration.  If  chemists  would  ex- 
amine the  question  as  to  effects  produced 
upon  timber  subjected  to  the  continual 
action  of  water  and  its  components,  or  to 
the  rise  and  fall  of  the  tide,  whether  salt 
or  fresh,  or  only  to  the  effects  of  a  certain 
amount  of  moisture,  as  in  the  case  of  rail- 
way sleepers  afterwards  dried  by  the  ac- 
tion of  the  sun,  the  practical  results  of 


127 

their  investigations  would   be  of   great 
value. 

Mr.  E.  A.  Cowper  said  he  understood 
that  an  examination  of  the  old  pieces  of 
timber  successfully  creosoted  that  had 
been  exhibited,  showed  they  were  not  at 
present  protected  by  tar  acids,  and  if 
they  had  had  any  in  them  in  the  first  in- 
stance, it  had  long  ago  evaporated.  The 
unsuccessful  telegraph  pole  exhibited  by 
Mr.  Carruthers,  from  which  a  specimen 
had  been  taken,  had  evidently  not  been 
put  into  a  creosoting  cylinder,  for  it  had 
a  mere  slight  covering  of  creosote  out- 
side. Hop-poles  were  often  put  into  an 
iron  pan  with  a  fire  under  it  and  made 
hot,  and  there  could  be  no  doubt  that 
steam  came  out  from  the  water  evaporat- 
ing, and  the  very  action  of  which  the  au- 
thor had  spoken  took  place  to  a  slight 
extent.  The  piece  of  wood  that  was  cut 
to  a  taper  had  a  little  creosote  in  its  end, 
but  on  its  sides  the  creosote  did  not  go 
in  jig-  of  an  inch,  it  was  merely  paint  on 
the  outside;  where  the  mortise-holes  had 
been  put  through  the  post  the  spores  had 


128 

entered  and  attacked  the  inside.  The  ef- 
fect of  a  spore  getting  into  a  piece  of 
timber  that  had  been  preserved  only  on 
the  outside  surface  was  no  argument 
against  the  preservation  of  timber  by 
creosote.  The  piece  from  the  Victoria 
Dock  fence,  which  had  been  well  creo- 
soted,  had  been  preserved,  and  was  as 
sound  as  it  was  twenty-nine  years  ago, 
when  it  was  put  down.  The  creosote 
had  gone  to  the  middle  of  the  wood  and 
protected  it.  The  other  specimen  had 
not  been  preserved,  and,  therefore,  it  was 
rotten.  A  very  extensive  series  of  ex- 
periments had  been  carried  out  by  Mr. 
Charles  Coisne,  and  they  were  of  a  very 
instructive  character.  Samples  of  creo- 
sote had  been  taken  from  England,  Scot- 
land, Belgium  and  France,  showing  15, 
15,  8  and  7  per  cent,  of  tar  acids,  and 
there  was  a  fifth  specimen  of  heavy  oil 
without  any  tar  acid.  Other  mixtures 
were  made  by  putting  in  an  extra  quan- 
tity of  tar  acids,  except  in  the  case  of  the 
one  kept  without  acid,  and  the  result 
showed  that  where  the  heavy  oil  was 


129 

used,  the  wood  was  preserved  in  the  best 
manner,  whilst  those  samples  of  wood 
preserved  with  creosote,  having  an  extra 
dose  of  acid,  were  not  so  well  preserved, 
and  that  which  was  unpreserved  was  en- 
tirely rotten.  He  had  gone  to  Silver- 
town  to  examine  the  apparatus  to  which 
reference  had  been  made.  There  were  a 
number  of  pipes  in  the  bottom  of  the 
creosote  cylinder  with  superheated  steam 
in  them.  When  the  timber  had  been 
put  into  the  cylinder  and  warm  creosote 
run  in  upon  it,  the  temperature  was  grad- 
ually got  up,  and  the  water  was  as  effect- 
ually driven  out  of  the  wood  by  evapora- 
tion as  would  be  the  case  if  water  was 
put  in  a  boiler  with  a  fire  under  it  and 
kept  without  any  fresh  supply  of  water. 
A  temperature  of  220°  or  230°  would 
evaporate  every  particle  of  moisture  out 
of  the  wood,  more  especially  when  a  vacu- 
um was  put  on.  He  might  mention  that 
the  vacuum  should  not  be  turned  on  sud- 
denly, otherwise  the  creosote,  steam,  and 
water  would  all  boil  over.  Water  was 
deposited  in  a  vessel  in  connection  with 


130 

the  condensing  pipe,  together  with  some 
light  hydro-carbons.  The  creosote  sup- 
plied to  the  creosoting  vessel  being 
heavy  oil,  would  not  commence  to  boil 
until  about  392°.  London  creosotes 
contained  about  4  to  7  per  cent,  of  tar 
acids.  He  had  himself  tried  some  ex- 
periments in  coagulating  and  precipitat- 
ing albumen,  and  he  found  that  consid- 
erably less  than  2  per  cent,  of  carbolic 
acid  in  the  creosote  would  precipitate 
the  largest  amount  of  albumen  found  in 
wood,  so  that  there  was  amply  sufficient 
carbolic  acid  in  the  London  creosote  for 
that  purpose.  Not  only  was  the  albu- 
men coagulated  by  the  two  per  cent,  of 
carbolic  acid,  but  by  the  mere  fact  of  its 
being  boiled.  If  an  egg  was  boiled  for 
a  short  time  the  white  would  set,  and  in 
an  hour  or  two  it  would  be  very  hard. 
After  the  vacuum  had  been  on  for  a  suf- 
.  ficient  time,  and  the  whole  of  the  water 
and  moisture  withdrawn  from  the  timber, 
the  cock  was  turned,  and  the  pressure 
put  on  with  pumps  up  to  120  Ibs.  to  the 
square  inch.  Not  only  did  the  pumps 


131 

put  on  the  pressure  and  force  the  creo- 
sote into  the  wood,  but  directly  the  tem- 
perature was  lowered  a  little,  steam  con- 
densed, and  there  was  a  vacuum  in  every 
pore  of  the  wood.  The  whole  of  the 
wood  was  made  a  condenser;  in  every 
pore  that  had  previously  contained  water 
there  was  a  vacuum,  so  that  the  creosote 
went  in,  and,  besides  that,  there  was  the 
pressure  of  120  Ibs.  to  the  square  inch. 
At  the  works  he  saw  a  whole  range  of 
tanks,  following  one  after  the  other.  He 
thought  the  method  was  a  very  practical 
and  mechanical  one.  There  could  be  no 
doubt  about  the  creosote  thoroughly  en- 
tering the  timber.  He  thought  the 
thanks  of  the  members  were  due  to  the 
author  for  the  admirable  way  in  which  he 
had  developed  the  subject.  The  only 
thing  wanted  was  a  sort  of  skeleton 
specification  for  their  guidance  in  the 
future. 

Mr.  W.  H.  Preece  said  that  as  the  be- 
havior of  certain  of  Her  Majesty's  tele- 
graph posts  had  been  called  in  question, 
he  ought  to  say  something  in  their  be- 


132 

half.  For  the  past  thirty  years  he  had 
devoted  all  the  attention  and  skill  that 
he  could  command  to  the  inquiry  as  to 
the  best  modes  of  preserving  timber. 
In  the  telegraph  service  of  the  country 
many  millions  of  poles  had  been  pre- 
served in  various  ways,  and  one  of  the 
methods — that  explained  by  the  author — 
had  proved  to  be  the  survival  of  the  fit- 
test. A  great  deal  had  been  said  as  to 
the  various  causes  of  decay.  Reference 
had  been  made  to  chemical  and  physio- 
logical causes,  but  there  was  a  third 
cause,  which  might  be  called  mechanical, 
of  the  decay  existing  at  the  "  wind  and 
water"  line,  or  the  ground  line,  where 
the  timber  was  exposed  to  incessant 
changes  of  moisture  and  temperature.  A 
careful  microscopic  examination  showed 
that  the  process  of  decay  was  a  purely 
mechanical  one,  that  the  wood  disinte- 
grated by  a  process  of  bursting.  The 
fibers  appeared  to  be  minute  boilers,  and 
the  change  of  temperature  produced 
evaporation,  minute  explosion,  and  rapid 
deterioration.  It  was  a  simple  thing  to 


133 

meet  the  chemical  cause  by  the  insertion 
of  salts  of  various  kinds,  and  it  was  pos- 
sible to  meet  the  physiological  cause  by 
antiseptic  treatment ;  but  the  mechanical 
cause  could  only  be  obviated  by  coating 
the  fibers  of  the  wood  with  waterproof 
material,  and  filling  them  with  a  thick, 
viscous  mass  like  creosote  in  its  best 
form.  In  1844  the  first  line  of  telegraph 
was  constructed  between  London,  South- 
ampton and  Gosport,  and  the  posts 
were  made  of  the  best  Memel  timber, 
preserved  by  the  burnettizing  process, 
simply  impregnating  the  wood  with  zinc 
chloride.  In  1857  he  made  a  personal 
observation  of  a  great  part  of  the  line  in 
different  grounds,  and  found  that  in  sand 
about  40  per  cent,  of  the  posts  had  gone, 
in  clay  about  33  per  cent.,  and  in  chalk 
about  28  per  cent.  In  1860  he  found 
that  the  proportion  was  much  greater, 
and  in  1871  they  had  all  failed,  so  that 
they  had  to  be  removed.  The  burnett- 
izing process  materially  added  to  the  life 
of  the  pole  without  rendering  it  inde- 
structible. Kyanizing  was  tried  to  a 


134 

small  extent,  but  the  poisonous  charac- 
ter of  the  salt  deterred  him  from  carry- 
ing it  further.  The  favorite  process 
about  twenty  years  ago  was  that  of 
boucherizing.  The  authorities  had  pur- 
chased whole  forests,  and  in  the  middle 
of  them  established  the  boucherizing 
process,  by  which  they  had  succeeded  in 
lengthening  the  life  of  timber  consider- 
ably. While  the  life  of  an  average  tele- 
graph pole  unprepared  was  about  seven 
years,  the. life  of  a  boucherized  pole  was 
about  fifteen  years.  In  1848  a  line  of 
poles  was  erected  from  Fareham  to  Ports- 
mouth, a  distance  of  about  20  miles,  and 
all  the  poles,  three  hundred  and  eighteen 
in  number,  were  creosoted  by  Mr.  Beth- 
ell.  It  1861  he  examined  them  all  in 
situ,  and  only  two  showed  the  slightest 
trace  of  decay,  and  they  had  begun  to 
decay  at  the  top.  In  1874  he  had  them 
again  examined,  and  every  pole  was 
sound.  Last  year,  owing  to  the  require- 
ments of  the  service,  and  the  necessity 
of  increasing  the  number  of  the  wires, 
the  line  of  poles  had  to  be  taken  down, 


135 

and  although  they  had  been  put  up  in 
1848,  they  were  as  sound  as  when  they 
were  first  erected.  About  the  year  1861 
the  question  of  the  proper  mode  of  pre- 
serving timber  was  one  of  great  conse- 
quence. The  authorities  were  not  satis- 
fied as  to  which  was  the  best,  boucher- 
izing  or  creosoting,  and  consequently,  as 
the  Yeovil  and  Exeter  line  of  the  Lon- 
don and  South- Western  Kailway  Com- 
pany the  poles  were  put  up  alternately  : 
first  a  plain  pole,  next  a  boucherized  pole, 
and  next  a  creosoted  pole,  the  line  ex- 
tending about  40  miles.  In  1870  he  had 
them  carefully  examined,  and  it  was 
found  that  of  the  plain  poles  that  had 
been  up  ten  years  not  one  existed,  all 
having  decayed;  while  of  the  boucher- 
ized poles  30  per  cent,  had  gone,  and  of 
the  creosoted  poles  not  one  had  decayed. 
The  result  was  that  the  Government  had 
decided  for  years  past  to  creosote  al] 
their  poles.  He  did  not  remember  the 
exact  specification  thut  was  used.  At 
present  the  millions  of  poles  existing  in 
the  country  were  all  creosoted.  It  was 


136 

true  that  some  of  them  had  failed,  but, 
as  Mr.  Carruthers  had  pointed  out,  there 
was  creasote  and  creosote.  There  were 
unreliable  firms,  and  others  in  whom  con- 
fidence could  be  placed ;  there  were  in- 
spectors who  could  be  trusted,  and  others 
who  could  not.  There  were  poles  about 
the  country  supposed  to  be  creosoted  that 
were  rotten  ;  and  it  had  been  found  that 
those  particular  poles  had  not  been  in- 
spected, and  that  they  had  been  hastily  and 
improperly  impregnated.  He  could  state, 
as  the  result  of  thirty  years'  experience, 
that  he  had  never  seen  a  case  of  a  prop- 
erly creosoted  pole  showing  the  slightest 
sign  of  decay. 

The  reply  of  Mr.  Boulton  upon  the 
Discussion  and  Correspondence  is  given 
at  the  end  of  the  Correspondence. . 

CORRESPONDENCE. 

Mr.  A.  Bouissou,  of  the  Western  Rail- 
ways of  France,  stated  that  in  1859,  on 
the  line  from  Rouen  to  Dieppe,  sleepers 
creosoted  by  the  Bethell  process  had 
been  adopted  for  the  first  time.  These 


137 

sleepers  were  of  beech.  They  had  been 
creosoted  in  England  in  the  works  of  the 
author's  firm,  and  when  an  examination 
of  them  was  made  twenty  years  later,  on 
the  occasion  of  the  Paris  Exhibition  of 
1878,  it  was  shown  that  not  a  single  one 
of  them  bore  the  slightest  trace  of  decay. 
Since  1864,  the  railway  company  of  which 
he  was  engineer  of  the  permanent  way, 
had  adopted  creosoting  for  their  sleep- 
ers, and  from  that  date  they  had  ap- 
plied it  to  about  five  million  sleepers, 
of  which  at  least  three  million  and  a-half 
were  of  beech  wood.  In  these  latter,  as 
in  the  trial  sleepers  of  1859,  no  sign  of 
decay  has  as  yet  been  distinguished,  and 
the  lasting  powers  of  the  sleepers  seemed 
only  to  be  limited  by  the  wear  and  tear 
to  which  the  materials  were  exposed. 
Beech  wood  placed  in  the  ground,  with- 
out having  been  prepared,  completely  de- 
cayed at  the  end  of  two  or  three  years, 
which  rendered  impossible  the  use  of 
that  wood  unprepared  in  the  form  of 
sleepers.  Also  sulphating,  employed  for 
a  long  time  for  beech  sleepers,  not  having 


138 

given  the  good  results  expected,  had  been 
abandoned  by  all  the  French  railway 
companies. 

The  employment  of  creosote  for  the 
preservation  of  sleepers  had  given  every 
satisfaction,  and  its  use  had  only  been 
limited  at  certain  periods  by  the  difficulty 
sometimes  experienced  in  procuring  a 
sufficient  quantity  of  creosote.  As  re- 
garded the  quality  of  the  creosote,  he 
simply  required  that  it  should  contain  5 
per  cent,  of  phenic  acid. 

Mr.  W.  A.  Brown  remarked  that  a  pre- 
serving process,  of  which  much  had  been 
said  and  a  great  deal  expected  by  engin- 
eers  a  few  years  ago,  had  been  referred 
to  in  the  latter  part  of  that  portion  of 
the  paper  devoted  to  "Apparatus  for 
Timber  Preserving."  This  process  was 
Mr.  Blyth's  system  of  "  Thermo- Carbol- 
ization,"  which  had  been  carried  out  by 
Messrs.  Conner  &  Co.  at  their  works  at 
Mill  wall,  when  a  large  number  of  sleep- 
ers had  been  prepared  for  some  of  our 
railways,  together  with  telegraph  poles 
for  them  and  for  the  Post  Office.  It  be- 


139 

X 

came  his  duty,  about  four  years  ago,  to 
inquire  into  the  subject,  and  he  made 
an  investigation  into  the  different  stages 
of  the  process  at  Messrs.  Conner  &  Co.'s 
works,  which  led  him  to  the  following 
conclusions : 

1st,  that  the  strength  of  the  wood  was 
impaired  through  some  of  the  celluloise 
and  its  incr listing  materials  being  carried 
off  in  the  form  of  pyroligneous  acid  by 
the  superheated  steam. 

2d,  that  the  peculiar  "  Creosote  mix- 
ture "  used  as  part  of  the  process,  con- 
tained so  large  a  proportion  of  water  that 
it  was  not  at  all  likely  to  act  as  a  pre- 
servative of  the  sleepers  to  which  it  was 
applied. 

It  would  be  interesting  to  hear  now 
how  the  sleepers  and  poles  thus  pre- 
pared had  actually  lasted  in  this  country. 
In  Austria  the  experience  of  Mr.  Seidl, 
and  in  France  that  of  the  author,  as  re- 
corded in  the  paper,  appeared  to  confirm 
the  conclusions  at  which  Mr.  Brown  ar- 
rived in  the  course  of  his  investigations ; 
but  so  far  as  he  was  aware,  there  were 


140 

no  published  results  as  to  the  process  in 
England. 

Mr.  John  Cleminson  observed  that  the 
question  of  preparing  timber  against  de- 
cay was  occupying  more  attention  now 
than  formerly.  It  was  therefore  to  be 
regretted  that  the  author  had  not 
referred  in  detail  to  many  good  proc- 
esses with  the  above  object  in  view, 
namely,  that  of  Sir  John  MacNeill, 
Gardner,  Beer,  Blythe,  and  others. 
The  author's  remarks  in  reference  to 
carbolic  acid  as  an  antiseptic  would 
lead  to  the  idea  that  it  was  necessary  the 
acid  should  remain  when  injected ;  such 
was  not  the  case,  nor  was  it  necessary. 
The  mere  fact  of  its  presence  (the  most 
powerful  antiseptic  known),  with  super- 
heated steam,  was  all  that  was  required 
to  produce  coagulation  of  the  albumen, 
and  so  to  render  preservation  practically 
complete.  With  the  old  process  of  creo- 
soting,  .the  surface  exteriorly  only  was 
preserved,  the  interior  if  unsound  decayed 
uninterruptedly.  All  depended  upon  the 
selection  of  the  timber.  No  amount  of 


141 

creosote  would  avail  to  save  its  destruc- 
tion ultimately,  if  the  interior  was  not 
sound.  Where  sleepers  were  adzed,  the 
greater  part,  and  in  many  instances  the 
whole  of  the  part,  penetrated  by  the 
creosote  was  cut  away,  thus  leaving  the 
interior  open  to  destruction  from  damp 
and  other  causes.  The  same  disadvantage 
was  experienced  in  the  case  of  piles, when 
the  ends  were  pointed  for  receiving  shoes 
after  creosoting.  With  carbolic  acid 
once  in  contact  with  the  albumen,  and  in 
the  event  of  any  interior  unsoundness, 
the  coagulation  arrested  decay,  and  pre- 
vented it  from  spreading,  by  entirely  en- 
closing the  defective  part  or  parts.  Com- 
bined when  necessary  with  an  outer  ap- 
plication of  creosote,  thorough  soundness 
and  preservation  internally  and  external- 
ly were  thus  secured.  Blythe's  process 
was  a  double  process.  The  object,  pres_ 
ervation  internally  and  externally,  in  the 
case  of  sleepers  and  piles,  was  most  ef- 
fectually obtained  by  carbolizing  the  in- 
terior, and  creosoting  the  exterior.  A  re- 
sult had  been  obtained  that  had  placed 


142 

this  process  foremost  with  French  en- 
gineers for  several  years,  and  it  was  now 
largely  used  by  them.  In  England  where 
used  it  had  met  with  much  favor.  The 
author  of  the  paper  was  employing  this 
process  in  France. 

Mr.  Richard  Cowper  remarked  that  the 
value  of  creosote  for  preserving  timber 
dspended  partly  on  the  mechanical  effect 
which  it  had  in  excluding  from  the  pores 
of  the  wood  air  and  water,  and  the 
germs  of  destruction  which  they  con- 
tained, and  partly  on  the  power  possessed 
by  certain  of  its  constituents  of  destroy- 
ing those  germs.  For  the  purposes  of 
germ- exclusion,  it  was  generally  admitted 
that  the  heavier  portions  of  the  creosote, 
from  the  less  degree  of  solubility  and 
volatility  which  they  possessed,  and  their 
property  of  solidifying  at  ordinary  tem- 
peratures, were  the  more  efficacious.  As 
regarded  the  germ-destroyers,  the  phe- 
nols and  the  alkaloids  alone  need  be  con- 
sidered. Phenols,  namely  carbolic,  cre- 
sylic,  and  other  acid  bodies  occurring  in 
creosote,  had  long  been  known  to  possess 


143 

remarkable  antiseptic  properties,  but  they 
were  easily  soluble  in  water,  and  com- 
paratively volatile.  Much  stress  had 
been  laid  upon  their  power  of  coagulat- 
ing albumen,  but  it  had  been  shown  that 
no  stable  chemical  compound  was  formed, 
and  that  the  albumen  thus  coagulated 
might  be  freed  from  the  phenol  by  wash- 
ing with  water,  when  it  would  decay.  It 
had  been  shown  by  the  experiments  of 
Coisne,  Greville  Williams,  and  the  author 
of  the  paper,  on  pieces  of  old  creosoted 
timber,  that  in  many  well  preserved  speci- 
mens no  phenol  can  be  detected  by  the 
ordinary  test,  whilst  in  most  cases  they 
had  found  naphthaline,  and  in  all  cases 
oils  of  the  heaviest  character  in  consider- 
able quantity.  It  had  been  shown  by  Mr. 
Greville  Williams  that  all  the  old  timbers 
examined  by  him  contained  a  consider- 
able amount  of  alkaloids,  and  his  experi- 
ments proved  not  only  that  these  alka- 
loids were  powerful  germicides,  but  that 
they  were  more  powerful  than  phenol. 
They  were  at  the  same  time  much  less 
soluble  and  volatile.  Evidently  if  creo- 


144 

sote  containing  a  high  percentage  of 
phenol  were  required,  it  could  not  con- 
tain so  high  a  percentage  of  the  heavier 
constituents,  which  were  those  possessing 
the  greatest  value  as  germ-excluders.  At 
the  same  time,  some  of  the  alkaloids 
which  had  been  shown  to  be  of  more 
value  than  phenol  as  germicides  would 
be  removed. 

Mr.  W.  Langdon  remarked  that  in  1874 
a  paper  by  him  upon  the  subject  had  been 
read  before  the  Society  of  Telegraph  En- 
gineers, in  which  he  warmly  advocated 
the  employment  of  creosote  in  preference 
to  any  other  preservative  for  timber,  and 
he  had  since  seen  no  reason  to  alter  the 
views  expressed  on  that  occasion.  Of 
late  years,  however,  the  appearance  of 
the  timber  so  treated  had  suggested  the 
belief  that  the  oils  now  employed  did  not 
contain  that  amount  of  tar  or  other 
heavy  compounds  which  was  apparently 
possessed  by  the  creosote  supplied  in  the 
earlier  eays.  His  attention  in  the  appli- 
cation of  creosote  to  timber  had  been 
more  in  the  direction  of  telegraph  poles 


145 

than  otherwise,  which  class  of  timber  was 
much  more  exposed  to  the  weather  than 
were  railway  sleepers,  and  which  might 
in  consequence  be  accepted  as  affording  a 
more  complete  test  of  the  value  of  the  oil 
than  did  railway  sleepers.  These  to  a  great 
extent  were  buried  in  the  soil,  and  had 
but  one  side  exposed  to  the  influence  of 
the  atmosphere.  Of  late  years  numbers 
of  the  poles  had  presented  anything  but 
the  appearance  of  a  well  creosoted  pole. 
The  surface  had  become  partially  or 
wholly. bleached,  and  almost  white.  This 
generally  occurred  on  that  portion  of  the 
pole  subject  to  the  sun's  rays;  but  it  was 
also  equally  marked  upon  that  side  of  the 
pole  exposed  to  prevailing  winds  and  wet 
weather.  It  would  therefore  seem  as  if 
the  bleaching  was  the  result  both  of  the 
influence  of  the  sun  and  of  the  weather ; 
in  fact  that  the  creosote  disappeared  from 
the  surface  of  the  pole  under  the  influ- 
ence of  the  sun  and  of  wet.  If  telegraph 
poles  creosoted  many  years  back  were 
examined,  as  a  rule  the  surface  of  those 
poles  would  be  found  covered  with  a 


146 

pitchy  compound,  and  that  mainly  on  the 
side  of  the  pole  exposed  to  the  sun. 
There  was  no  washing  out  from  the 
weather.  This  he  thought  was  easy  of 
explanation.  The  warm  atmosphere  would 
always  exercise  an  extractive  influence 
upon  any  oil  injected  into  wood  or  other 
like  substance ;  its  tendency  would  be  to 
bring  it  to  the  surface,  where  the  lighter 
portions  would  be  evaporated,  and  the 
heavier  portions  congealed.  Creosote  no 
doubt  was  a  strong  antiseptic,  but  where 
timber  when  felled  was  decayed,  it  could 
not  give  fresh  life  to  the  decayed  portion. 
Timber,  if  properly  seasoned,  would  last 
many  years  if  not  exposed  to  the  vicissi- 
tudes of  wind  and  weather,  as  in  the  in- 
stance of  many  articles  of  furniture  made 
from  the  very  same  wood  from  which 
telegraph  poles  and  railway  sleepers  were 
obtained,  and  which  seemingly  never  de- 
cayed indoors.  It  was  here  that  the  cre- 
osote process  enabled,  an  equally  long 
life  to  be  obtained  for  it  when  employed 
out  of  doors,  and  he  imagined  that  the 
heavier  oils  played  a  much  higher  part  in 


147 

procuring  this  immunity  from  decay  than 
the  creosote  oil,  inasmuch  as  it  was  to 
these  heavier  oils  that  the  exclusion  of 
moisture  from  the  timber  was  due.  A 
telegraph  pole,  or  a  railway  sleeper,  free 
from  disease,  if  properly  seasoned,  and 
encased  in  such  a  manner  as  to  prevent 
moisture  getting  into  its  fiber,  was  prac- 
tically indestructible  from  rot  or  decay. 
The  coating  given  to  it  by  the  injection 
of  these  heavier  oils  into  the  fiber  to  a 
depth  of  from  1  to  2  inches  afforded  the 
timber  this  coating,  excluded  moisture, 
and  thereby  secured  its  duration. 

Mr.  C.  De  Laune  Faunce  De  Laune  re- 
marked that  the  author  had  attempted  to 
prove  that  only  a  very  small  quantity  of 
carbolic  acid  was  necessary  in  creosote  for 
the  preservation  of  wood.  He  approached 
the  subject  with  diffidence,  as  he  lay 
claim  to  no  scientific  knowledge,  merely 
discussing  it  from  the  purely  practical 
side ;  and  because  he  had  been  instru- 
mental in  extending  the  use  of  creosote 
among  landowners  and  farmers.  The 
author  referred  to  his  having  used  creo- 


148 

sote  too  hot,  and  thereby  having  dam- 
aged the  wood,  much  in  the  same  way  as 
if  he  had  taken  a  warm  bath  too  hot.  He 
certainly  stated  to  the  author  that  he  had 
used  a  material  called  creosote  which 
contained  a  very  small  percentage  of 
carbolic  acid,  and  that  the  wood  had 
failed  to  be  satisfactorily  impregnated 
with  it  in  an  open  tank,  even  when  sub- 
mitted to  a  great  heat ;  but  he  scarcely 
anticipated  that  he  would  infer  that  it 
was  his  general  custom  to  use  extreme 
heat,  as  he  only  wished  it  to  be  under- 
stood that  even  under  such  conditions 
the  creosote  did  not  perfectly  penetrate 
into  the  wood.  The  process  of  injec- 
tion, in  the  case  of  telegraph  poles,  might 
preserve  them  to  an  indefinite  period, 
but  such  a  course  was  frequently  im- 
practicable to  the  former,  and  in  the  case 
of  hop-poles  impossible ;  wherefore  an 
open  tank  was  indispensable.  For  the 
last  twenty  years  he  had  used  creosoted 
wood,  and  the  process  had  always  been 
performed  in  an  open  tank.  The  wood 
was  first  cut  to  the  required  shape,  -and 


149 

then  immersed  in  the  creosote  which 
had  previously  been  liquefied  and  warmed 
by  a  furnace  built  underneath  the  tank. 
No  thermometer  had  ever  been  used  to 
regulate  the  heat,  and  the  only  precau- 
tion taken  was  to  prevent  the  creosote 
from  boiling  over,  though  it  was  suffi- 
ciently heated  to  make  a  few  bubbles  ap- 
pear on  the  surface.  Wood  of  all  kinds 
had  been  used,  and  no  difficulty  in  ap- 
plying the  creosote  was  at  first  experi- 
enced, but  he  believed  that  the  creosote 
had  gradually  been  becoming  worse  and 
worse,  and  so  he  submitted  it  to  Dr.  Voeck- 
ler  for  analysis,  and  got  the  following 
reply:  "Your  creosote  has  a  specific 
gravity  of  1.103,  and  on  being  subjected 
to  distillation  yields  only  61  per  cent,  of 
volatile  oils,  of  which  4  per  cent,  are  car- 
bolic acid."  My  experience  in  creosoting 
timber,  small  as  it  is  when  compared 
with  that  of  public  companies,  is  large 
for  a  private  individual,  as  I  have  at 
this  time  46 £  miles  of  fences  where 
creosoted  wood  is  used ;  and  whereas 
the  system,  when  employed  some  years 


150 

ago,  was  satisfactory,  the  present  results 
are  as  much  the  contrary.  The  pieces 
of  creosoted  wood  exhibited  by  Mr.  Car- 
ruthers  were  creosoted  by  me  in  1866, 
and,  as  was  pointed  out  by  him,  are  per- 
fect in  their  preservation.  Unfortunately 
I  have  no  analysis  of  the  creosote  then 
used,  for  such  an  analysis  would  prove 
that  a  material  of  the  same  constituents 
would  be  suitable  for  preserving  wood 
in  an  open  tank.  It  was  obvious,  there- 
fore, that  a  creosote  was  formerly  used 
that  could  and  did  preserve  inferior  wood 
in  an  open  tank  perfectly,  and  which 
could  be  used  so  easily  that  no  particular 
precautions  as  to  the  dryness  of  the  wood 
were  necessary,  and  it  was  in  the  hope  of 
ascertaining  the  component  parts  of  the 
creosote  which  he  once  used  with  such 
admirable  results,  that  he  ventured  on 
these  remarks ;  for  the  creosote  that  he 
formerly  used  for  preserving  wood  was 
as  valuable  as  that  which  he  was  now  us- 
ing was  useless  and  worthless,  and  all 
he  asked  of  manufacturers  was  to  give 
him  material  like  what  he  had  before. 


151 

Mr.  W.  Lawf ord  wished  to  inquire  how 
it  was  that,  in  the  face  of  such  undoubt- 
ed proofs  of  the  value  of  the  creosot- 
ing  process,  some  of  the  large  railway 
companies,  and  notably  the  Midland, 
had  given  up  creosoting  their  sleepers  ? 
He  considered  it  the  duty  of  every  one 
who  used  timber  largely  to  adopt  either 
this  or  some  other  antiseptic  treatment, 
since  large  encroachments  were  annually 
made  upon  the  timber-growing  districts 
of  the  world,  without  an  adequate  sup- 
ply of  timber-producing  trees  being 
planted  for  the  use  of  posterity. 

Mr.  C.  Lowe,  in  reference  to  the  con- 
stituents of  the  creosotes  employed  for 
" pickling"  or  preserving  timber,  was 
disposed  to  attribute  to  the  tar  acids 
only  a  very  small  amount  of  the  effective 
results  obtained  by  the  application  of 
the  creosote,  for  the  following  rea- 
sons : 

1.  Carbolic  and  cresylic  acids  were 
both  completely  volatile  even  at  an  aver- 
age summer  temperature  in  England, 
and  in  hot  climates  could  not  long  re- 


152 

main  present  (except  as  traces)  in  any 
timber  to  which  they  had  been  ap- 
plied. 

2.  Both  these  acids  were  readily  solu- 
ble in  water,  and  would  consequently  be 
rapidly  removed  from  the  timber  in  case 
the  latter,  previously  saturated  with 
them,  was  subjected  to  the  action  of 
water  in  motion.  He  regarded  the  ac- 
tion of  coal-tar  creosote  in  preserving 
timber  as  presenting  a  two-fold  char- 
acter ;  firstj  a  mechanical  action,  by  which 
the  wood  was  rendered  waterproof  from 
the  filling  up  of  the  cellular  tissue  with 
matter  insoluble  in  water ;  second,  a 
chemical  or  antiseptic  action,  due  chiefly 
to  the  presence  of  the  tar  acids.  These 
tar  acids  were  roughly  divisible  into  the 
•readily  volatile  acids  soluble  in  water 
(carbolic  and  cresylic),  and  the  heavy, 
almost  non-volatile,  acids  insoluble  in 
water.  The  latter  class  had  not  been 
thoroughly  studied,  but  it  was  known  to 
be  powerfully  antiseptic,  and  anti-para- 
sitic. He  therefore  considered  the  creo- 
sote best  adapted  for  the  "  pickling  "  of 


153 

. 

timber  to  be  a  creosote  containing  suf- 
ficient solid  hydrocarbon,  such  as  naph- 
thaline, to  be  solid  at  a  temperature 
slightly  above  the  average  climatic  or 
other  temperature  to  which  the  timber 
was  to  be  ultimately  exposed  ;  at  the 
same  time,  to  prevent  the  attacks  of 
parasitic  insects,  etc.,  the  heavy  tar  acids 
should  be  present.  No  reliance  should 
be  placed  on  carbolic  and  cresylic  acids 
for  pickling  timber,  seeing  they  were  so 
readily  removed  by  the  action  of  water 
and  climatic  heat.  It  was  well  known 
that  their  albuminous  combinations  were 
readily  broken  up  by  simple  washing 
with  water;  as  germicides  and  anti- 
septics, when  retained  in  situ,  these 
acids  were  invaluable  for  surgical  use 
and  disinfection,  and  to  these  purposes* 
they  should  be  relegated. 

Mr.  T.  E.  M.  Marsh  exhibited  speci- 
mens of  timber  used  by  the  late  Mr. 
Brunei  in  1839.  These  were  fair  samples 
of  the  bulk  of  the  timber  of  the  ribs 
of  the  skew  bridge  over  the  River  Avon, 
at  the  Bath  station  on  the  Great  West- 


154 

ern  Railway.  The  timber  was  cut  from 
Memel  balk,  and  was  kyanized.  It  was 
quite  sound  after  forty  years'  service. 
The  kyanjzing  process  had  been  em- 
ployed extensively  by  the  late  Mr.  Brunei 
in  the  early  works  of  the  Great  Western 
Railway.  The  permanent-way  timbers 
were  thus  prepared,  and  gave  excellent 
results  as  to  preservation  from  decay, 
as  was  shown  by  specimens  cut  from 
various  parts  of  the  line,  between  Lon- 
don and  Bristol,  after  having  been  laid 
from  fifteen  to  twenty  years.  Mr.  Marsh 
had  gained  much  experience  in  the  prep- 
aration and  uses  of  creosoted  timber, 
both  while  acting  for  Mr.  Brunei,  and 
subsequently  up  to  the  present  time.  In 
the  early  days  of  the  process,  the  tar 
from  which  creosote  was  prepared  was 
not  subjected  to  the  extraction  of  so 
many  chemical  ingredients  as  was  now 
the  case,  and  the  naphthaline,  or  salt 
precipitated  was  comparatively  small, 
and  considered  of  little  value.  No  diffi- 
culty was  then  experienced  in  getting  a 
good  admixture  of  light  and  heavy  oil  in 


155 

a  fluid  state,  of  satisfactory  color,  con- 
sistency and  taste,  and  complying  with 
the  rough  and  ready  tests  adopted.  Mr. 
Brunei  adopted  the  process  extensively 
from  its  early  introduction  by  Mr. 
Bethell,  in  bridges  and  permanent  way, 
and  much  of  those  timbers  and  struc- 
tures remained  in  use  at  the  present 
day.  It  was,  however,  soon  discovered 
that  it  was  of  great  importance  the  tim- 
ber should  be  well  seasoned  and  dry, 
and  that  it  was  worse  than  useless  to 
creosote  unseasooed,  damp  or  wet  tim- 
ber. Some  alarming  cases  of  internal 
decay  had  been  discovered,  attributable 
to  these  causes.  Of  late  years,  on  ac- 
count of  the  greater  demands  on  the 
timber  merchants,  and  for  other  reasons, 
the  preparation  of  creosoted  timber  had 
not  always  had  such  careful  considera- 
tion. The  processes  were  often  carried 
on,  not  only  not  under  cover,  but  water 
in  variable  quantities  was  generally 
found  in  the  tanks  from  which  the  oil 
was  pumped  into  the  pressure-cylinders, 
and  solid  salts  and  a  mixture  of  mud  and 


156 

the  residuum  and  drainage  of  objection- 
able matter  from  the  timber  of  preceding 
charges,  accumulated  in  the  tanks  and 
returned  again,  to  the  detriment  of  sub- 
sequent charges.  It  not  unfrequently 
happened  that  timber  coming  from  the 
pressure-cylinders  might  be  found  with 
some  portions  presenting  no  trace  what- 
ever of  creosote  even  on  the  surface,  but 
showing  only  signs  of  the  contact  of 
dirty  water,  when  the  quantity  of  creo- 
sote injected  was  supposed  to  have  been 
50  gallons  to  the  load.  Such  facts,  Mr. 
Marsh  asserted,  were  sufficient  to  ac- 
count for  many  reported  failures,  with- 
out reference  to  the  chemical  questions 
as  to  the  relative  values  of  the  constitu- 
ent parts  of  the  oil.  Mr.  Marsh's  in- 
structions to  his  inspectors  for  the  prep- 
aration and  pickling  of  timber,  where 
thorough  efficiency  was  desired,  were 
based  on  his  own  personal  observa- 
tions, and  were  as  follows  : 

"The  state  of  the  tanks  from  which 
the  creosote  is  being  drawn  while  the 
pressure  progresses,  and  before  any 


157 

creosoting  is  done,  must  be  examined, 
and  if  found  to  contain  salty  or  muddy 
sediment  at  the  bottom,  or  water  at  the 
top,  or  the  nature  of  the  creosote  other- 
wise bad,  its  use  must  be  protested 
against.  Samples  must  be  taken  by  a 
tube  dipped  to  test  the  liquid  at  various 
depths,  particularly  the  upper  and  lower 
portions  of  about  12  inches  of  the  top, 
and  the  same  at  the  bottom.  This  must 
be  strictly  attended  to.  No  steam  shall 
be  let  into  the  creosote  anywhere.  The 
numerous  pipes  used  for  heating,  and 
sometimes  hoses  and  joints,  may  give  the 
means  of  mixing  in  steam  during  the 
process,  and  hence  the  condensed  water, 
which  must  not  be  permitted  under  any 
circumstances.  Sometimes  the  appear- 
ance of  the  timber  after  creosoting  will 
show  that  water  has  been  in  contact  with 
it.  The  thorough  good  creosoting  must 
also  be  checked  by  a  chisel  at  the  sound 
hearty  parts  of  the  timber,  and  the 
penetration  checked  by  weighing  trial 
sticks  with  each  charge  (these  should 
not  be  open  sappy  timbers,  and  they 


158 

should  be  the  least  dry  rather  than  those 
to  favor  absorption  more  than  the  bulk 
in  the  same  charge).  A  good  percent- 
age, over  50  glallons  to  the  load,  must  be 
injected  so  as  to  allow  for  outside  drain- 
age when  drawn  out  of  the  cylinder.  In 
weighing,  50  gallons  may  be  reckoned  as 
550  Ibs.  If  the  timber  be  not  quite  sat- 
isfactory and  perfectly  dry,  and  immedi- 
ate delivery  is  urgently  wanted,  then  a 
considerable  extra  quantity  must  be  in- 
jected, as  much  as  10  per  cent.,  or  fur- 
ther drying,  and  under  Cover,  must  be 
insisted  upon,  but  in  no  case  must  posi- 
tively wet  or  damp  timber  be  allowed  to 
go  into  the  pressure-cylinders." 

Mr.  Benjamin  Nickels  observed 
that  he  was  much  gratified  in 
noting  that  the  author  had  drawn 
special  attention  to  the  compound 
acridine,  pointing  out,  at  the  same 
time,  its  high  antiseptic  value  as  a  con- 
stituent of  creosoting  materials.  It  would 
appear  that  his  impressions  had  been 
based  on  certain  marked  properties  ex- 
hibited by  this  peculiar  substance,  no- 


159 

tably  its  intense  pungency,  acridity,  and 
high  antiseptic  value,  also  its  immunity 
from  loss  by  evaporation  and  the  solvent 
action  of  water.  As  little  beyond  a  mere 
reference  to  the  compound  had  been 
made,  it  might  be  of  interest  to  state 
what  had  been  done  in  other  directions, 
and  so  far  as  it  might  corroborate  the 
views  advanced  by  its  author.  In  the 
year  1882  he  was  induced  to  take  out  a 
patent  for  a  composition  to  be  used  as  an 
insecticide,  and  for  the  coating  of  ships' 
bottoms  and  other  submerged  surfaces, 
and  in  which  acridine  played  an  import- 
ant part.  He  had,  during  a  previous  ex- 
perience, met  with  many  opportunities  of 
observing  the  painfully  irritating  action 
of  the  heavier  tar  oils,  arising  from  hand- 
ling during  the  treatment  and  purifica- 
tion of  anthracine,  due  to  the  presence 
of  acridine,  and  as  an  outcome  of  the  ob- 
servation it  had  occurred  to  him  that  this 
substance  should  constitute  an  effective 
"  antifoul,"  inasmuch  as  it  would  be  al- 
most impossible  for  animal  life  to  remain 
in  contact  with  it.  Experiment  in  nu- 


160 

merous  directions  fully  supported  the 
idea ;  but  the  question  arose,  would  the 
acridine  resist  the  prolonged  solvent  ac- 
tion of  water,  and  remain  effective  for  a 
lengthened  period,  and  in  the  thin  coat- 
ing of  any  composition  that  could  be  aP- 
plied  as  a  paint  to  a  ships'  side?  Opin- 
ion varied  considerably  as  to  ultimate 
success  when  attempted  on  a  practical 
scale,  although  laboratory  trials  had  shown 
that  such  composition  was  unacted  upon 
in  still  water.  The  first  experiment  of 
any  importance  was  made  on  a  small  iron, 
barque  (the  "Cordova")  which  sailed 
from  London  for  the  Falkland  Islands 
about  the  end  of  January,  1882,  return- 
ing at  the  end  of  October,  after  an  ab- 
sence of  nine  months,  during  which  her 
hull  had  been  constantly  submerged. 
Previous  to  sailing,  portions  of  her  plates 
towards  the  lower  part  of  the  vessel,  and 
where  subjected  to  the  greatest  wash, 
had  been  coated  in  the  ordinary  way  of 
applying  a  ship's  paint  with  acridine 
composition,  prepared  in  conformity  with 
the  patent  referred  to.  He  was  present 


161 

on  her  return  to  England,  and  upon  the 
vessel  being  docked  for  repainting  and 
repair,  he  made  a  close  inspection  of  the 
portion  that  had  been  originally  coated 
with  the  composition.  He  found  that 
the  paint  had  remained  intact,  presenting 
a  smooth  and  unbroken  surface ;  it  had 
adhered  most  tenaciously  to  the  iron 
plates,  completely  protecting  them  from 
the  action  of  the  sea.  There  was  no  ad- 
hesion of  barnacle  or  weed,  and  the  evi- 
dence of  contained  acridine  was  very 
manifest  on  applying  the  tongue  to  por- 
tions of  the  composition  scraped  from 
the  side  of  the  vessel.  Subsequent  ex- 
amination showed  that  there  had  been 
little  or  no  loss  of  acridine,  and  that  the 
prolonged  and  be.iting  action  of  swiftly- 
running  and  boisterous  seas  had  failed 
in  removing  or  washing  out  the  acridine 
originally  incorporated  in  the  paint  ap- 
plied. Since  the  date  of  this  experiment 
many  others  had  been  made,  and  were 
still  on  hand,  with  vessels  on  long  sea- 
voyages,  and,  as  far  as  he  was  enabled 


162 

to  state,  the  results  obtained  had  been  of 
a  satisfactory  charactei\ 

It  would  be  difficult,  perhaps,  to  cite 
more  complete  illustrations  of  the  indif- 
ference of  a  substance  to  severe  water  ac- 
tion ;  and  the  author  might,  he  thought, 
rest  well  assured  that  his  statements 
concerning  this  singular  tar  product  were 
in  nowise  overrated  or  exaggerated.  As 
regarded  the  antiseptic  character  of  acri- 
dine,  he  might  mention  that  it  was  of 
high  value,  extremely  small  quantities  be- 
ing sufficient  to  arrest  the  change  in 
many  organic  substances  prone  to  rapid 
decomposition. 

Mr.  Martin  F.  Roberts  wished  to  di- 
rect attention  to  a  point  which  had  in- 
fluenced engineers  in  their  preference  for 
the  so-called  "  Country  oil,"  viz.,  that  of 
economy.  Engineers  would  be  aware 
that  in  drawing  up  specifications  it  was 
usual  to  stipulate  for  a  certain  quantity 
of  creosote  to  be  injected  into  a  cubic 
foot  of  timber,  usually  6,  8  or  10  Ibs., 
the  contractor's  price  for  creosoting  be- 
ing regulated  according  to  the  quantity 


163 

specified ;  and  it  thus  became  necessary 
for  engineers  to  consider  whether,  say  8 
Ibs.  per  cubic  foot  of  the  thick,  heavy, 
London  creosote  penetrated  as  far  into 
the  timber  as  8  Ibs.  of  the  thinner  coun- 
try oils.  He  was  sure  all  engineers  would 
agree  that  it  would  not ;  and  from  his 
own  experience  he  was  able  to  say  that, 
with  telegraph  poles,  in  many  places 
where  8  Ibs.  of  London  creosote  per  cu- 
bic foot  had  been  injected,  it  had  not 
penetrated  more  than  half  through  the  sap- 
wood,  whereas  a  similar  quantity  of  coun- 
try oil  would  have  penetrated  completely 
to  the  heartwood,  although,  of  course,  the 
country  oil  would  not  leave  as  large  a  de- 
posit of  solid  substances  in  the  pores  of 
the  timber.  It  was,  therefore,  desirable 
to  consider  whether  it  was  better  to 
have  the  sap  wood  completely  injected 
with  thin  oil  at  a  certain  price,  or  the 
outer  portion  only  injected  with  thick 
oil  at  the  same  cost,  and  his  experience 
led  him  to  prefer  the  complete  injection 
by  the  thin  oil.  His  ground  for  arriving 
at  this  conclusion  was  that,  although  he 


164 

had  met  with  many  samples  of  creosoted 
timber  in  which  a  portion  of  the  sap- 
wood  had  decayed  where  the  creosote 
had  not  penetrated,  he  had  never  met 
with  a  piece  of  timber  having  decayed 
where  the  creosote  had  penetrated,  except 
in  one  instance  in  a  Government  tele- 
graph pole,  referred  to  in  the  discussion  ; 
and  even  in  this  case  he  thought  it  well 
to  ask  if  the  decay  had  taken  place  before 
or  after  creosoting.  Engineers  acquaint- 
ed with  red  fir  timber  would  remember 
that  what  was  called  a  "  foxey  pole  "  was 
occasionally  found,  in  which,  although 
the  outer  portion  or  all  of  the  sapwood 
might  be  quite  sound,  some  of  the  inner 
portion  of  the  pole  had  decayed  before 
felling  ;  and  it  was  often  a  difficult  mat- 
ter, even  for  an  experienced  inspector,  to 
detect  such  a  pole.  It  would  easily  be 
conceived  that  in  such  a  case  the  decay 
might  be,  and  often  was,  attributed  to  a 
defective  quality  of  creosote  having  been 
used,  instead  of  to  the  fact  that  a  por- 
tion of  the  pole  was  rotten  when  treated. 
The  remarks  made  by  the  author  un- 


165 

der  the  heading  of  "  The  Conflicting 
Theories  of  Putrefaction,"  in  which  he 
spoke  of  the  "  gaping  orifice  of  a  crack 
produced  by  the  sun  in  a  piece  of  tim- 
ber," would  appear  to  specially  point  to 
the  necessity  for  the  use  of  a  thin,  pene- 
trating oil,  as  timber  would  crack  after 
long  exposure  in  the  sun,  even  if  it  had 
been  creosoted  with  the  thickest  London 
oil ;  and  in  these  cases  the  oil  which  had 
penetrated  the  deepest  would  be  more  ef- 
fective, as  it  was  the  most  likely  to  have 
genetrated  beyond  the  depths  of  the 
crack.  If  it  were  the  practice  to  com- 
pletely saturate  the  entire  mass  of  tim- 
ber with  creosote,  and  if  it  were  found 
possible  to  do  so  in  all  cases,  there  would 
then  be  no  objection  to  the  use  of  Lon- 
don oils ;  but  as  the  question  of  cost  had 
to  be  considered,  and  the  smallest  quan- 
tity of  creosote  per  cubic  foot  which  was 
found  to  answer  the  purpose  was  there- 
fore specified  for,  the  thinner  country  cre- 
osote was  preferred,  owing  to  its  greater 
penetration,  weight  for  weight.  In  Mr. 
Coisne's  experiment  with  shavings,  the 


166 

conditions  were  so  totally  different  to 
those  met  with  in  ordinary  practice,  that 
too  much  reliance  should  not  be  placed 
in  them.  It  was  obviously  an  easy  mat- 
ter to  completely  saturate  shavings  either 
with  thick  or  thin  creosote,  but  with 
telegraph  poles  and  railway  timber  the 
creosote  never  penetrated  completely 
through  the  timber,  and  it  could  not  be  con- 
tended that  the  exclusion  of  germs  alone 
prevented  putrefaction,  as,  if  so,  a  coating 
of  tar  would  prevent  decay.  What  was 
necessary  was  that  the  germs  of  decay  in 
the  timber  should  also  be  destroyed,  and 
this  could  only  be  accomplished  by  bring- 
ing all  that  portion  of  the  timber  more 
liable  to  decay — viz.,  the  sapwood — under 
the  influence  of  a  creosote  of  consider- 
able penetrating  power.  If  evidence  in 
support  of  this  assertion  were  needful, 
it  would  only  be  necessary  to  refer  to  the 
fact  that  engineers  strictly  barred  the 
use  of  whitewood  timber  for  telegraph 
poles  and  other  purposes,  owing  to  its 
being  found  impossible  in  practice  to  in- 
ject creosote  into  whitewood  to  a  greater 


167 

depth  than  J  or  f  of  an  inch  from  the 
surface,  and  whitewood  timber  so  pre- 
pared, either  with  London  or  country 
creosote,  was  found  to  decay  rapidly.  It 
would  appear  that  the  best  system 
of  creosoting  would  consist  in  first  in- 
jecting the  timber  with  thin  "country 
oil,"  then  running  the  thin  oil  off  and 
filling  the  cylinder  with  London  creosote, 
which,  being  forced  in  by  increased 
pressure,  would  drive  the  thinner  oil  fur- 
ther into  the  timber,  and  the  thicker  cre- 
osote would  hermetically  seal  the  outer 
pores  of  the  timber.  Failing  this  proc- 
ess, owing  to  its  increasing  the  cost,  it 
would  appear  advisable  to  use  thin  creo- 
sote, and  if  it  was  considered  that  thin 
oil  did  not  sufficiently  fill  the  outer  pores 
of  the  timber,  the  process,  at  a  trifling 
cost,  could  be  siipplemented  by  giving 
the  timber  a  coat  of  hot  tar. 

Mr.  Greville  Williams  stated  that  he 
regarded  the  paper  as  the  most  valuable 
and  exhaustive  contribution  yet  made  to 
the  literature  of  the  subject.  He  agreed 
with  Dr.  Meyrnott  Tidy  and  the  author  in 


168 

considering  that  the  value  of  the  carbolic 
acid  in  creosote  oils  had  been  overrated. 
He  believed  that  an  oil  from  which  the 
carbolic  acid  had  been  removed  would 
sterilize  wood,  if  thoroughly  impregnated 
with  it,  partly  by  virtue  of  the  organic 
alkaloids  present,  and  partly  by  the  pro- 
tective influence  of  the  heavier  oils  them- 
selves. He  had  satisfied  himself  by  care- 
ful experiments  that  the  alkaloids  exer- 
cised a  potent  influence  in  preventing  the 
development  of  bacteria,  mould,  and  mi- 
croscopic fungi  in  vegetable  infusions. 
He  thought,  moreover,  that  where  wood 
had  to  be  exposed  to  the  action  of  sea- 
water,  it  would  be  advantageous  to  use  a 
creosote  containing  a  high  percentage  of 
the  alkaloids ;  this  could  easily  be  attained 
by  well-known  methods.  Although  the 
minute  quantities  of  carbolic  acid  remain- 
ing in  old  creosoted  timbers  were  too  small 
to  account  for  their  preservation,  he  con- 
sidered it  right  to  say  that,  by  a  suffi- 
ciently delicate  method  of  manipulation, 
he  had  rarely  failed  in  getting  evidence 
of  its  presence  even  thirty  years  after  the 


169 

-wood  had  been  creosoted.  He  found 
traces  of  it  in  eleven  out  of  fourteen 
specimens  which  had  been  creosoted  from 
twenty- five  to  thirty-two  years  before. 
The  organic  alkaloids,  however,  which  re- 
mained, were  sufficient  to  allow  quantita- 
tive estimation.  He  thought  that  no  chem- 
ist, who  had  examined  very  old  sleepers 
for  carbolic  acid,  could  come  to  any  other 
conclusion  than  that  the  traces  remaining 
were  insufficient  for  their  protection.  A 
point,  moreover,  of  great  importance  for 
the  proper  comprehension  of  the  subject, 
was  involved  in  this  almost  entire  disap- 
pearance of  the  carbolic  acid.  If  the  co- 
agulation of  the  albumen  by  the  carbolic 
acid  were  the  cause  of  the  preservation 
of  the  timber,  how  was  it  that  this  acid 
almost  entirely  disappeared?  The  in- 
stability of  the  compound,  of  albumen 
with  carbolic  acid,  was  well  known  to 
those  chemists  who  had  minutely  exam- 
ined it ;  nothing  more  conclusively  proved 
this  instability  than  the  disappearance  of 
the  carbolic  acid.  With  regard  to  the 
naphthaline,  he  thought  it  significant  that 


170 

it  was  only  absent  from  two  of  the  sleep- 
ers he  had  examined.  There  could,  he 
considered,  be  no  question  that  naphtha- 
line, although  perhaps  feeble  as  a  germi- 
cide, properly  so  called,  was  very  valuable 
as  a  sterilizer ;  it  was  insoluble  in  water, 
and  once  in  the  wood,  clung  to  it  tena- 
ciously. He  was  also  most  decidedly  in 
favor  of  the  removal  of  all  restrictions  as 
to  maximum  boiling-point,  and  considered 
that,  if  the  oils  were  fluid  at  the  temper- 
ature of  injection  (say  100°  to  120° 
Fahrenheit),  that  was  all  that  was  need- 
ful. On  the  whole  question,  he  found 
himself  able  to  thoroughly  indorse  the 
conclusions  of  the  author  and  Dr.  Tidy, 
and  he  considered  that  specifications 
which  excluded  the  use  of  London  oils 
were  framed  under  a  misapprehension  of 
the  true  nature  of  the  condition  requisite 
to  afford  a  good  creosote. 

Mr.  Boulton  had  been  obliged  to  be 
very  brief  in  his  verbal  reply  at  the  close 
of  the  discussion,  and  as  some  of  the 
points  then  raised  involved  matters  of 
considerable  detail,  which  had  also  been 


171 

alluded  to  in  the  correspondence,  he 
thought  that  unnecessary  repetition  would 
be  avoided  if  he  were  to  connect  his  re- 
plies to  both  series  of  communications  in 
a  continuous  form.  He  was  gratified  at 
the  valuable  support  which  his  main 
propositions  had  received. 

The  remarks  made  by  Dr.  Tidy,  and 
the  views  expressed  by  that  gentleman  in 
his  recent  report  to  the  Gaslight  and 
Coke  Co.  were  in  principle  in  accordance 
with  the  views  expressed  in  the  paper. 
The  author,  however,  believed  with  Dr. 
Armstrong  that  Dr.  Tidy,  who  had  been 
somewhat  conservative  on  the  subject  of 
tar  acids,  would  be  led  by  the  logic  of 
facts  to  accept  a  much  lower  proportion 
than  8  per  cent.  The  "London  creo- 
sotes "  as  they  came  from  the  still,  honest 
creosotes  which  had  done  excellent  work, 
and  which  constituted  probably  about 
one  half  of  the  total  supply  of  this  king- 
dom, did  not  contain  so  large  a  percent- 
age. Some  misapprehension  still  existed 
on  this  subject,  which  the  statement  of  a 
few  facts  might  remove.  In  July,  1863, 


172 

the  author  sent  to  Dr.  Letheby  a  sample 
of  the  usual  London  creosotes,  which  he 
was  then  largely  using.  Dr.  Letheby 
found  it  contained  only  4.37  per  cent,  of 
tar  acids.  Later  on,  and  during  one 
period  of  seven  years  especially,  nearly 
the  whole  of  the  tar  of  the  great  London 
Gas  Companies,  as  well  as  tar  from  other 
sources,  was  contracted  for  and  distilled 
by  the  author's  firm.  The  quantity  was 
probably  larger  than  had  ever  been  treated 
up  to  that  time  by  any  one  firm  or  cor- 
poration, and  it  therefore  formed  a  suf- 
ficiently broad  basis  for  estimation.  He 
would  give  the  quantities  during  three 
^consecutive  years — 

1877  Gallons  of  tar  distilled....  14,735,404 

1878  "          "          "        ....  15,839,819 

1879  "        '"          "        ....  12,690,029 

or  an  average  of  between  fourteen  and 
fourteen  and  a  half  million  of  gallons  per 
annum.  He  had  found,  as  stated  in  the 
paper,  that  the  heavy  oils  distilled  from 
this  mass  of  tar  contained  on  an  average 
from  4  to  7  per  cent,  of  total  tar  acids. 
More  recent  experiments  which  he  had 


173 

made  upon  a  large  number  of  London 
tars — one  series  in  May,  1882,  another  in 
August,  1882,  and  a  third  since  this  paper 
had  been  read — gave  similar  results. 
Latterly,  the  largest  of  the  English  gas 
companies,  the  Gaslight  and  Coke  Co.,, 
had  erected  works  at  Beckton,  at  which 
they  distilled  their  own  tar.  It  had  been 
assumed  that  the  list  of  analyses  ap- 
pended to  Dr.  Tidy's  printed  report  rep- 
resented the  percentage  of  tar  acids  which 
the  London  creosotes  in  their  natural 
condition  contained.  This,  however,  was 
not  the  case.  The  samples  analyzed  by 
Dr.  Tidy  contained  from  8.2  to  10.2  per 
cent,  of  tar  acids,  but  they  had  been  spe- 
cially treated  to  "meet  the  market,"  cre- 
ated by  the  modern  type  of  specification 
by  removing  from  the  creosote  some  of 
its  least  volatile  parts,  those  parts  con- 
taining little  or  none  of  the  volatile  tar 
acids.  The  Gaslight  Co.'s  creosotes  as 
they  came  from  the  still  contained  on  an 
average  6  per  cent,  of  total  tar  acids  by 
the  ordinary  caustic  alkali  test.  The  au- 
thor had  been  enabled  to  clear  up  this. 


174 

matter,  of  which  experts  would  readily 
detect  the  importance,  owing  to  the  court- 
esy of  the  Board  and  Secretary  of  the 
Gaslight  and  Coke  Co. 

He  agreed  with  Dr.  Armstrong  in  the 
importance  of  M.  Pasteur's  experiment 
upon  sawdust,  which  was  recorded  in  the 
Comptes  Kendus  of  the  Academic  des 
Sciences  for  1863.  It  is  remarkable  as 
an  early  demonstration  of  the  application 
of  the  germ  theory  to  the  phenomena  ac- 
companying the  decay  of  woody  fiber. 
Dr.  Armstrong  had  alluded  to  the  dis- 
tinction between  wood  creosote  and  tar 
creosote.  Both  contained  tar  acids,  some 
of  which  might  be  identical,  or  if  not 
identical,  isomeric.  But  tar  creosote,  if 
it  could  be  so  called,  was  a  complex  body ; 
some  of  the  tar  acids  it  contained  differed 
essentially  from  either  carbolic  or  cresylic 
acid,  being  less  volatile,  and  less  soluble 
in  water  than  either  phenol  or  cresol. 
There  is  evidently  room  for  much  further 
investigation  in  this  connection ;  also  for 
a  more  complete  comparison  between  the 


175 

"  tar  acids  of  the  coal-tar  oils  and  similar 
bodies  contained  in  other  oils." 

In  relation  to  the  remarks  of  Mr.  W. 
Foster,  the  author  must  express  the  hope 
that  that  gentleman  would  continue  the 
very  interesting  researches  of  which  he 
had  so  recently  given  an  account  to  the 
Institution  in  his  valuable  paper  on  "  The 
Composition  of  Coal."  Authentic  Tables 
as  to  the  varying  products  derived  from 
different  kinds  of  coal,  and  at  different 
temperatures,  were  becoming  matters  of 
the  first  necessity  in  various  branches  of 
industry.  Mr.  Foster  had  referred  to 
the  experiment  of  Pettigrew,  alluded  to 
in  the  paper.  Pettigrew  had  removed 
the  embalming  material  from  the  heart  of 
the  mummy  by  steeping  it  in  alcohol ; 
after  which,  upon  exposure  to  the  atmos- 
phere, putrefaction  took  place.  What 
the  author  desired  to  point  out  was  that 
the  previous  immunity  from  decay  had 
not  been  the  result  of  any  chemical  com- 
bination between  the  antiseptic  and  the 
tissue. 

A  jarring  note  had  been  struck  by  Mr. 


176 

Barnber,  who  had  represented  "the whole 
secret  of  the  paper"  to  consist  in  "the 

author's  idea that  nothing  should  be 

left  in  the  creosote  which  it  would  pay 
him  better  to  take  out ;"  an  object  foreign 
to  the  declared  aim  and  intention  of  the 
paper.  The  author  had  not  approached 
the  subject  from  the  commercial  point  of 
view — a  fact  which  the  President  had  so 
gracefully  recognized.  It  might,  how- 
ever, be  opportune  to  state  that  he  was 
not  at  present  commercially  interested  in 
any  manufacture  which  caused  carbolic 
.acid  to  be  "taken  out"  of  the  creosote 
oils,  although  he  was  largely  interested 
in  the  success  of  prepared  timber  as  an 
engineering  material,  and  therefore  in 
the  choice  of  the  best  antiseptics  for  that 
purpose,  whether  obtained  from  the  creo- 
sote oils  or  from  other  sources.  Mr.  Bam- 
ber's  figures  as  to  the  comparative  com- 
mercial values  of  creosote  oils  and  car- 
bolic acid,  recalled  to  memory  the  well- 
known  comparison  between  the  value  per 
ton  of  iron  ore  and  of  steel  watch  springs. 
The  manufacture  of  pure  carbolic  acid  was 


.  177 

a  long  and  costly  process,  of  which  the 
first  cost  of  the  crude  material  formed  an 
altogether  insignificant  item.  Nor  was 
so  low  a  price  as  2d.  per  gallon  for  creo- 
sote either  "proverbial"  or  usual.  But 
it  would  be  found  in  the  long  run  that 
the  consumer  had  to  pay  the  commercial 
value  for  everything  which  the  creosote 
contained,  and  it  was  therefore  best  to 
discuss  upon  scientific  and  practical 
grounds  the  substances  which  the  engin- 
eer should  require  it  to  contain.  It  was  one 
of  the  main  objects  of  the  paper  openly  to 
point  out  by  diagrams  and  detailed  de- 
scriptions the  principal  substances  con- 
tained in  the  coal-tar  oils,  to  draw  atten- 
tion to  their  properties,  and  to  state  their 
uses  for  various  manufactures,  so  that  for 
the  purposes  of  timber-preserving,  engin- 
eers might  be  in  a  position  to  "  prove  all 
things,  hold  fast  that  which  is  good." 
Mr.  Bamber  was  mistaken  as  to  facts  in 
his  allusion  to  Dr.  Letheby's  specification, 
and  that  of  Dr.  Tidy.  Dr.  Letheby's 
specification,  drawn  up  under  instructions 
from  Mr.  Meadows  Kendel,  M.  Inst.  C.E., 


178 

in  1865,  for  the  use  of  the  East  Indian 
Railway  Company,  stipulated  that  the  creo- 
sote was  to  yield  to  a  solution  of  caustic 
potash,  not  less  than  5  per  cent,  of  crude 
carbolic,  and  other  tar  acids.  Dr.  Letheby 
never  increased  that  quantity.  Dr.  Tidy 
had  increased,  and  not  as  Mr.  Bamber 
supposed,  diminished  the  percentage  of 
tar  acids  mentioned  by  Dr.  Letheby. 

Mr.  Bamber  complained  that  no  facts 
or  data  had  been  given  respecting  Dr. 
Tidy's  experiments  on  naphthaline.  But 
the  paper  contained  a  reference  to  a 
printed  report  of  Dr.  Tidy,  deposited  in 
the  library  of  the  Institution,  wherein  was 
a  full  account  of  these  experiments.  They 
were  also  recorded  and  approved  of  by 
Dr.  Lunge,  of  Zurich,  in  his  learned  work 
upon  "The  Distillation  of  Coal  Tar." 
Amongst  other  authorities  who  after  in- 
vestigation differed  from  Mr.  Bamber  in 
admitting  naphthaline  as  an  ingredient  in 
the  timber-preserving  oils,  were  the  late 
Mr.  Bethell,  Mr.  Burt,  Prof.  Sir  Frederick 
Abel,  Mr.  Forestier,  for  the  French  Gov- 
ernment, Mr.  Coisne,  for  the  Belgian  Gov- 


179 

eminent,  &c.  Mr.  Bamber  had  once  stated 
to  an  eminent  engineer,  in  a  report  upon 
a  creosote  highly  charged  with  naphtha- 
line, that  timber  impregnated  with  such 
an  oil  would,  "  within  a  very  short  time 
of  the  timber  being  in  India,  lose  5  Ibs. 
out  of  every  10  Ibs.  put  into  the  timber 
here  merely  by  escape  of  naphthaline.'' 
Dr.  Tidy's  experiments  with  timber  in- 
jected wholly  with  naphthaline,  and  sub- 
jected to  a  temperature  of  130°  Fahren- 
heit, proved  that  these  apprehensions 
were  unfounded.  But  it  was  now  related 
by  Mr.  Bamber  that  in  his  own  experi- 
ment a  piece  of  wood  impregnated  with  a 
creosote  of  the  type  which  he  preferred, 
and  containing  20  per  cent,  of  tar  acids, 
lost  in  four  weeks  42.33  per  cent,  of  the 
oil  taken  up.  Mr.  Bamber' s  record  of  his 
own  experiment  was  very  instructive.  He 
tried  two  kinds  of  creosote  against  each 
other.  One,  which  might  be  called  speci- 
men A,  was  "full  of  naphthaline,"  but  the 
percentage  of  that  body  was  not  stated. 
It  contained  10  per  cent,  of  tar  acids. 
Specific  gravity  not  named.  With  this- 


180 

oil  a  piece  of  deal  3  inches  by  3  inches 
by  8  inches  was  impregnated.  The  other, 
which  might  be  called  specimen  B,  was  a 
".country  oil,"  specific  gravity  1.045,  con- 
taining 20  per  cent,  of  tar  acids.  "With 
this  oil  a  piece  of  deal  3  inches  by  3 
inches  by  6  inches  was  impregnated. 
Specimen  A  was  alluded  to  as  "  Mr. 
Boulton's  own  oil "  and  "  the  author's 
London  creosote ;"  but  to  these  appella- 
tions he  demurred,  as  he  never  used  a  10 
per  cent,  creosote  unless  required  to  do 
so  by  specification,  and  the  London  oils 
did  not  in  their  natural  state  contain  10 
per  cent,  of  tar  acids.  Therefore  A,  al- 
though it  might  come  from  his  works, 
would  be  a  mixture  of  London  and  Coun. 
try  oils.  But,  although  in  the  author's 
judgment  too  volatile,  yet  the  10  per  cent, 
specimen  would  be  less  volatile  than  the 
20  per  cent.  Therefore,  the  author  pre- 
ferred A  to  B.  Where  a  large  issue  was 
staked  upon  a  single  minute  experiment, 
accuracy  of  result  should  be  ensured  by 
the  most  minute  precautions.  It  was  not 
explained  why  the  two  pieces  of  deal  were 


181 

not  cut  to  the  same  size,  a  circumstance 
which  affected  the  conditions  both  of  ab- 
sorption and  of  evaporation.  Nor  were 
the  specific  gravities  of  the  two  pieces  of 
wood  stated.  Of  two  pieces  cut  from  the 
same  log,  one  piece  of  wood  would  fre- 
quently absorb,  under  the  same  condi- 
tions, a  very  much  larger  quantity  of  fluid 
than  the  other.  However,  the  results  as 
stated  might  be  calculated  as  follows : — 

A.  Piece  of  wood,  capacity  72   cubic 
inches,  absorbed  1,020  grains  of  creosote 
=3.49  Ibs.  per  cubic  foot. 

B.  Piece  of  wood,  capacity  54   cubic 
inches,  absorbed  1,785  grains  of  creosote 
=8.17  Ibs.  per  cubic  foot. 

But  no  pressure  was  used,  and  engin- 
eers would  recognize  that  the  experiment 
failed  to  reproduce  the  conditions  of  the 
ordinary  creosoting  cylinder.  It  was  well 
known  that  without  pressure,  light  oils 
penetrated  timber  more  easily  than  heavy 
oils.  In  like  manner  the  adulterating 
substance,  bone  oil,  penetrated  more 
readily  than  creosote;  solutions  of  me- 
tallic salts  more  readily  still ;  and  water 


182 

more  readily  than  all.  But  it  was  "  light 
come,  light  go ; "  those  which  penetrated 
most  readily  were  generally  the  least 
permanent.  The  main  object  of  the  en- 
gineer was  not  to  select  the  fluid  which 
gave  the  contractor  the  least  trouble  to 
inject.  He  desired  to  select  the  antisep- 
tic which  was  likely  to  be  the  most  effi- 
cacious and  the  most  permanent,  and  he 
required  the  contractor  to  provide  effi- 
cient apparatus,  and  to  inject  under 
pressure  a  stipulated  quantity  by  weight. 
Sleepers  and  large  logs  of  timber  were 
injected  without  difficulty  with  creosotes 
of  a  heavier  type  than  either  of  Mr. 
Bamber's  samples,  and  to  the  extent  of 
10  Ibs.  and  12  Ibs.  per  cubic  foot.  Small 
pieces  of  wood  could  be  easily  gorged 
with  creosotes.  The  author  had  recently 
injected  some  fir  paving  blocks  6  inches 
by  6  inches  by  3  inches,  with  22  Ibs.  per 
cubic  foot  of  ordinary  heavy  London  cre- 
osote, containing  about  5  per  cent,  of  tar 
acids.  Mr.  Batnber  exposed  his  speci- 
mens to  evaporation  on  a  mantelshelf  at 
a-  temperature  never  above  70°  Fahren- 


183 

heit,  and  generally  between  40°  Fahren- 
heit and  50°  Fahrenheit.  In  four  months 
A  had  lost  47.75  per  cent.,  and  B  had 
lost  42.33  per  cent,  of  the  creosote  put 
in.  If  this  could  be  taken  as  a  normal 
result,  engineers  would  hesitate  as  to  em- 
ploying either  type  of  creosote.  No  doubt 
both  were  too  volatile.  But  it  should 
also  be  borne  in  mind  that  the  injection 
was  imperfect ;  to  use  Mr.  Bamber's  "  ex- 
pression, it  was  only  "  skin  deep."  As 
regarded  the  comparative  evaporation  of 
the  two  specimens,  hpwever,  the  result 
was  extremely  valuable.  It  is  well-known 
that  the  evaporation  of  fluids  (except 
when  in  a  state  of  ebullition)  was  in  pro- 
portion to  the  surface  exposed,  and  not  to 
the  bulk  of  the  fluid.  This  point  Mr. 
Bamber  appeared  to  have  forgotten ;  he 
had  exposed  A,  the  creosote  he  disliked, 
to  a  wider  evaporating  surface  than  that 
to  which  he  had  exposed  B,  the  creosote 
which  he  preferred.  The  position  on  the 
mantelshelf  in  which  the  pieces  of  wood 
were  placed  was  not  stated.  But  sup- 
posing them  to  have  been  suspended,  say 


184 

by  a  thread,  so  that  all  the  surfaces  were 
exposed  to  evaporation  equally,  the  re- 
sults might  thus  be  calculated : 

A.  Piece  of  wood,  the  sum  of  whose 
superfices  was   114   square   inches,  lost 
487  grains  =  4.29  grains  per  square  inch 
of  exposed  surface. 

B.  Piece  of  wood,  the  sum  of  whose 
superfices  was  90  square  inches,  lost  575 
grains =6. 39  grains  per  square   inch  of 
exposed  surface. 

If,  however,  each  piece  of  wood  had 
been  placed  with  one  of  its  sides  in  con- 
tact with  the  mantelshelf,  so  that  one 
surface  was  protected  from  evaporation, 
the  calculation  became  slightly  modified, 
so  that  A  would  have  lost  5.41  grains, 
and  B  7.98  grains  per  square  inch  ex- 
posed. If  the  specimens  had  been  placed 
on  end,  then  A  showed  a  loss  of  4.64 
grains  and  B  of  7.09  grains  per  square 
inch.  Mr.  Bamber  had  therefore  been 
mistaken  as  to  the  comparative  volatili- 
ties of  naphthaline  and  the  tar  acids,  as 
proved  by  his  own  experiment.  B,  the 
creosote  with  20  per  cent,  of  tar  acids, 


185 

had  lost  about  50  per  cent,  more  than  A, 
the  creosote  with  10  per  cent,  of  tar 
acids  and  "  full  of  naphthaline."  Had  it 
been  otherwise,  every  chemical  treatise 
describing  the  properties  of  these  bodies, 
would  have  to  be  re-written.  The  state- 
ment that  part  of  the  loss  of  specimen  B 
was  due  to  the  fact  that  some  of  the  oil 
drained  out  of  it,  which  it  was  said  u  was 
not  fair  "  to  that  specimen,  gave  rise  to 
the  rejoinder,  was  it  quite  fair  to  a  tim- 
ber-preserving process  that  a  type  of  an- 
tiseptic should  be  recommended  which 
"  drained  out "  with  so  little  provocation  ? 
This  part  of  the  discussion  might  almost 
appear  trivial,  were  it  not  for  the  fact, 
confirmed  by  many  special  instances  in  the 
author's  experience,  that  whenever  these 
light  oils  had  been  used  exclusively, 
whether  for  marine  work  or  for  railways, 
complaints  invariably  arrived,  sooner  or 
later.  Oils  of  so  light  and  volatile  a  na- 
ture lost  a  large  portion  of  their  bulk, 
which  evaporated  or  drained  out  in  the 
creosoting  yard,  on  the  export  ship,  and 
on  the  permanent  way  in  India  and  else- 


186 

where.  An  experiment,  easy  to  carry  out 
without  any  laboratory  apparatus,  may  be 
tried  by  any  one  interested  in  this  sub- 
ject. Take  three  saucers  or  shallow 
dishes ;  place  in  one  saucer  200  grains  of 
pure  carbolic  acid  (crystallized),  in  the 
second  200  grains  of  pure  cresylic  acid, 
and  in  the  third  200  grains  of  pure 
naphthaline.  Expose  them  side  by  side 
in  any  room,  and  at  any  ordinary  tem- 
perature. The  crystals  of  carbolic  acid 
would  liquefy  in  a  few  minutes-,  owing  to 
the  avidity  with  which  that  body  absorbed 
moisture  from  the  atmosphere.  In  a  few 
weeks'  time  (varying  with  the  temperature) 
the  carbolic  acid  would  have  entirely 
disappeared  by  evaporation.  By  that 
time  the  cresylic  acid  would  have  lost 
about  half  its  bulk.  When  the  whole  of 
the  cresylic  acid  had  also  evaporated. 
The  naphthaline  in  considerable  bulk,  at 
least  one-half  of  the  original  weight 
would  still  remain,  an  easy  victor  in  the 
trial  of  endurance.*  The  evaporation  was 

*  This  experiment  was  carried  out  on  a  mantelshelf 
at  the  Institution  of  Civil  Engineers  in  August,  1884, 
with  the  result  indicated  by  Mr.  Boulton. 


'187 

greatly  retarded  by  the  incorporation  of 
those  bodies  with  the  less  volatile  oils, 
and  by  their  being  driven  into  the  cells 
of  the  timber.  But  the  evaporation  must 
necessarily  take  place  in  proportion  to  the 
respective  and  recognized  volatilities. 

Allusion  had  been  made  by  Mr.  Bamber 
to  "  charred  oil,"  and  he  presumed  that 
it  was  a  residue  of  anthracene  manufac- 
ture. The  author  in  the  course  of  his 
experience  had  never  met  with  "  charred 
creosote,"  except  indeed  as  a  result  of 
over-heating  in  a  laboratory  experiment ; 
nor  was  he  acquainted  with  any  ordinary 
process  of  manufacture  by  which  it  could 
be  produced.  Creosote  oils  were  distil- 
lates ;  whatever  the  heat  in  the  still,  the 
residuum  might  become  carbonized,  but 
not  the  substances"  which  came  over  in 
the  form  of  vapor.  Anthracene  or  para- 
naphthaline  had  been  denounced  by  the 
creosote  specifications  of  the  theorists  at 
a  time  when  it  was  considered  worthless 
for  any  purpose  ;  it  was  taken  out  of  the 
creosote  by  every  tar-distiller  in  England, 
whether  in  London  or  country,  and  was 


188 

now  of  value  for  the  manufacture  of  ali- 
zarine. The  removal  was  effected  by  a 
simple  process  of  filtration  ;  the  resulting 
oils  were  the  green  oils,  the  best  part  of 
creosote  for  timber-preserving,  fluent  and 
rich  in  alkaloids.  How  could  they  become 
"  charred  oils  ?  " 

In  the  illustration,  drawn  from  a  fire- 
engine,  it  was  forgotten  that  a  fire  might 
break  out  a  second  time,  and  that  if  a 
fresh  supply  of  water  were  not  available, 
the  building  would  be  consumed.  Car- 
bolic acid  evaporated  rapidly  from  timber, 
and  it  had  been  proved  that  it  left  no 
permanent  effects  behind.  When  the 
sleeper  was  placed  in  the  permanent  way 
the  supply  of  the  antiseptic  could  not  be 
renewed,  and  the  timber  would  rot  if 
more  stable  antiseptics  were  not  present 
in  the  shape  of  the  heavier  oils. 

As  regarded  naphthaline  colors  Mr. 
Bamber  was  also  mistaken.  They  were 
very  successful  as  a  manufacture,  and 
their  use  was  largely  increasing.  He 
accused  the.  author  of  "condemning 
country  oils,"  and  of  saying  that  they 


189 

"  were  not  good  for  creosoting  timber." 
In  the  paper  the  exact  contrary  was 
stated.  The  author  advocated  the  use  of 
both  London  and  country  oils,  and  he 
habitually  used  large  quantities  of  both. 
What  he  condemned  was  the  use  of  oils, 
whether  London  or  country,  which  were 
so  manipulated  as  to  contain  a  large  pro- 
portion of  volatile  substances  at  the  ex- 
pense of  the  more  durable,  and  therefore 
for  this  purpose  more  valuable  antisep- 
tics. Were  Mr.  Bamber's  theories  carried 
into  practice,  about  one-half  of  the  creo- 
sote manufactured  in  England,  the  enor- 
mous bulk  of  the  "London  oils,"  would 
be  excluded  from  use  by  the  timber-pre- 
server. Nevertheless  they  were  precisely 
the  creosotes  which  had  given  the  most 
unmistakably  good  results,  whether,  as 
in  the  case  of  the  early  Indian  sleepers, 
and  of  the  sleepers  of  the  Chemin  de  Fer 
de  1'Ouest,  the  percentage  of  tar-acids 
had  been  proved  to  be  small,  or  whether, 
as  was  the  practice  of  the  Belgian  Gov- 
ernment, the  tar-acids  had  been  altogeth- 


190 

er  and  avowedly  struck  out  of  the  speci- 
fication. 

In  reply  to  Prof.  Yoelcker,  lie  desired 
to  state  that  he  had  purposely  abstained 
from  connecting  the  names  of  administra- 
tive bodies  with  the  questions  of  contro- 
versy. He  was  not  aware  of  any  specifi- 
cation officially  issued  by  the  War  Office 
which  bore  on  this  subject;  but  it  was 
known  that  the  distinguished  chemist 
of  that  department  had  been  consulted 
by  various  administrations,  who  could 
have  had  no  other  object  in  view  than  to 
obtain  the  best  engineering  material.  The 
views  of  Sir  Frederick  Abel  on  all  the 
most  important  points  of  a  creosote  spe- 
cification were  substantially  the  same  as 
those  of  Dr.  Tidy  and  of  the  author.  And 
what  the  author  considered  to  be  the 
most  important  points  were,  1st,  that  the 
presence  in  considerable  volume  of  the 
heavier  and  least  volatile  distillates,  i.  e., 
those  distilling  at  or  above  600°  Fahren- 
heit, must  not  merely  be  tolerated  but 
insisted  upon.  That  naphthaline,  and 
the  other  usual  semi-solid  constituents, 


191 

should  be  admitted,  provided  they  were 
completely  fluid  at  the  temperature  to 
which  the  creosote  was  raised  when  in- 
jected into  the  wood.  It  was  known  that 
these  views  had  not  been  adopted  by  the 
Crown  agents  for  the  colonies,  but  he 
hoped  that  this  discussion  might  be  the 
means  of  clearing  away  many  misconcep- 
tions. Respecting  the  point  which  he 
considered  subsidiary  to  the  other  two, 
although  not  unimportant,  viz.,  the  per- 
centage of  tar  acids,  Sir  Frederick  Abel, 
as  well  as  Dr.  Tidy,  had  recently  recom- 
mended a  reduction,  and  the  last  word 
had  not  been  said  on  this  question.  Prof. 
Yoelcker  was  mistaken  in  thinking  that 
Dr.  Tidy  had  recommended  8  per  cent, 
of  carbolic  acid.  The  8  per  cent,  was  of 
total  tar  acids,  including  carbolic,  cresylic, 
and  all  other  tar  acids  which  could  be  re- 
moved by  a  specified  solution  of  caustic 
soda.  Dr.  Tidy,  in  his  report  to  the  Gas- 
light Co.,  mentioned  his  reasons  for  not 
stipulating  for  a  fixed  quantity  of  carbolic 
acid.  Whenever  any  stated  quantity  of 
this  body  had  been  mentioned  in  specifi- 


192 

cations  by  English  engineers,  it  had  been 
fixed  at  one-half  of  the  total  tar  acids. 
Hence  the  quantity  had  varied  from  2-J 
per  cent,  to  5  per  cent.,  the  latter  being 
the  largest  quantity  of  crude  carbolic  acid 
which  the  author  had  ever  known  to  be 
required  by  any  specification  issued  in 
this  country.  He  might  be  permitted  to 
express  his  satisfaction  that  Dr.  Voelcker 
had  recently  joined  the  ranks  of  investi- 
gators into  the  properties  of  creosote  oils, 
but  he  was  sure  that  so  distinguished  a 
chemist  would  be  the  last  to  depreciate 
the  experiments  and  experience  of  the 
numerous  chemists  and  practical  men  who 
had  placed  the  results  of  their  labors  on 
record.  It  could  surely  have  only  been 
by  some  misconception  that  Dr.  Yoelcker 
recommended  an  entirely  new  departure 
by  asking  for  10  per  cent  of  carbolic  acid 
in  creosotes  used  for  young  timber  or 
sap-wood,  although  he  admitted  the  prob- 
able superiority  of  the  heavier  oils  for 
timber  intended  for  railway  sleepers  and 
other  engineering  purposes.  Dr.  Yoelcker 
had  not  produced  the  results  of  any  orig- 


193 

inal  experiments  in  support  of  his  views. 
The  typical  experiments  which  he  asked 
for  had  been  tried  and  recorded ;  they 
proved  that  carbolic  acid  and  the  lighter 
tar  acids  were  not  reliable  as  durable 
antiseptics  for  timber.  Engineers  were 
familiar  with  the  preparation  of  young 
wood  and  sap-wood  as  well  as  with  that 
of  older  timber.  The  same  creosotes 
were  always  used  for  both,  and  with  com- 
plete success.  It  had  been  clearly  estab- 
lished that  the  heavy  oils  preserved  sap- 
wood  from  decay.  It  would  be  remem- 
bered by  many  members  of  the  Institu- 
tion that  the  late  Mr.  Bethell  had  even 
advocated  the  use  of  young  wood  in  pref- 
erence to  older  timber,  because  the  sap- 
wood  absorbed  the  creosote  so  readily, 
and  that  Mr.  (now  Sir  John)  Hawkshaw 
had  combated  this  idea,  not  from  any 
doubt  of  the  preservation  of  young  wood, 
but  upon  the  ground  that  the  engineer 
must  choose  for  many  purposes  the  kind 
of  timber  best  adapted  for  resisting  im- 
pact or  heavy  strains.  Amongst  the  nu- 
merous successful  specimens  of  creosoted 


194 

wood  which  had  been  exhibited  at  the 
Institution  during  the  discussion,  and 
whichfhad  been  taken  from  various  rail- 
ways after  periods  of  endurance  varying 
from  sixteen  to  thirty- two  years,  nothing 
was  more  striking  than  the  perfect  pres- 
ervation of  the  sap-wood,  although  careful 
analysis  had  shown  that  the  heavy  oils, 
and  not  the  tar  acids,  were  the  enduring 
agents  of  preservation.  The  allusion  of 
Dr.  Voelcker  to  telegraph  poles  had  elic- 
ited much  practical  information.  Nothing 
could  be  more  conclusive  than  the  evi- 
dence of  Mr  Preece  as  to  the  behavior 
of  the  young  timber,  surrounded  by  its 
girdle  of  sap-wood,  which  was  used  for 
telegraph  poles  in  this  country.  The  au- 
thor had  been  responsible  for  the  creo- 
soting  of  a  large  portion  of  the  poles  al- 
luded to  by  Mr.  Preece ;  these  had  as  a 
rule  been  prepared  with  the  usual  Lon- 
don oils.  But  it  was  only  right  that  he 
should  state  another  circumstance.  He 
believed  that  the  success  of  the  poles, 
creosoted  for  the  Post-office  Telegraph 
Department,  was  largely  influenced  by  the 


195 

care  taken  by  that  department  in  the 
seasoning  of  the  timber.  The  date  of  de- 
livery of  the  poles,  landed  and  stacked  at 
the  creosoting  yard,  was  a  matter  of  con- 
tract, but  there  was  no  fixed  date  for  the 
creosoting.  On  the  contrary,  the  engi- 
neer did  not  allow  them  to  be  creosoted 
until  he  pronounced  them  to  be  dry,  and 
ready  for  the  process.  Sixteen  years  ago, 
at  a  meeting  of  the  Institution,  he  had 
urgently  recommended  the  adoption  of 
some* such  method  for  ensuring  the  proper 
seasoning  of  timber.  The  very  interest- 
ing and  satisfactory  evidence  of  Mr. 
Bouissou,  the  Engineer  of  the  West  of 
France  Railways,  confirmed  the  experi- 
ence of  Mr.  Preece,  both  as  to  the  satis- 
factory results  of  creosoting,  and  also  as 
to  the  great  importance  of  seasoning  be- 
fore creosoting;  the  precautions  adopted 
for  the  latter  purpose  by  the  French 
company  being  substantially  the  same  as 
those  of  the  English  administration.  With 
reference  to  the  preparation  of  telegraph 
poles,  a  very  valuable  paper  had  been 
contributed  by  Mr.  William  Langdon, 


196 

M.  Inst.  C.  E.,  to  the  Society  of  Telegraph 
Engineers,  on  the  25th  of  March,  1874. 
Mr.  Langdon  had  also  contributed  to  this 
discussion,  and  had  confirmed  by  his  ex- 
perience many  of  the  views  entertained 
by  the  author.  With  regard,  therefore, 
to  the  observations  of  Dr.  Yoelcker  as  to 
green  or  unseasoned  timber,  the  author 
would  add  the  results  of  his  own  long 
and  varied  experience  in  this  and  other 
countries,  by  saying  that  the  attempt 
should  never  be  made  to  inject  creosote, 
or  any  other  oily  substance,  without  pre- 
viously, or  at  the  time  of  the  operation, 
expelling  watery  moisture.  Timber  should 
not  be  felled  whilst  the  sap  was  in  it. 

As  regarded  the  effects  of  living  organ- 
isms, and  the  introduction  of  their  spores 
through  cracks  in  the  wood,  the  views  of 
Mr.  Carruthers  entirely  agreed  with  those 
expressed  by  the  anthor.  But  what  was 
the  remedy  ?  The  botanical  aspect  of  the 
question  had  not  been  lost  sight  of,  from 
the  days  when  Dean  Buckland  and  others 
discussed  at  this  Institution  the  question 
of  timber  preparation  from  that  important 


197 

standpoint,  and  it  had  not  been  overlooked 
in  the  modern  systems  of  injection.  Exo- 
genous trees,  whose  annual  growth  took 
place  by  the  formation  of  concentric  layers 
of  vascular  tissue  added  externally,  fur- 
nished the  timber  with  which  engineers 
had  almost  exclusively  to  deal.  The 
softer  and  younger  wood,  containing  the 
greatest  portion  of  albumen,  was  on  the 
outside  ;  it  was  more  liable  to  decay  than 
the  harder  portions.  It  was  the  chief 
merit  of  the  system  of  injecting  under 
pressure  that  it  precisely  met  this  diffi- 
culty. The  softer  parts  absorbed  more 
of  the  antiseptic  than  the  rest,  the  press- 
ure followed  the  line  of  least  resistance, 
the  antiseptic  fluid  gorged  the  sap-wood, 
and  penetrated  to  all  cracks  or  shakes. 
There  was  but  little  analogy  between  this 
method  and  the  application  of  a  surface 
coating  of  pitch,  as  although  he  recom- 
mended by  preference  oils  of  a  heavy 
character,  and  containing  semi-solids,  the 
whole  of  these  bodies  were  perfectly 
liquid  at  100°  Fahrenheit,  the  tem- 
perature to  which  they  were  usually 


198 

subjected  at  the  time  of  injection.  On 
cooling,  they  solidified,  not  on  the  surface 
merely,  but  within  the  pores  of  the  tim- 
ber, which  they  sealed  up  against  the  in- 
cursion of  the  agents  of  decay.  Mr. 
Carruthers  had  referred  to  the  experi- 
ments of  the  celebrated  Dr.  Koch.  The 
researches  of  Koch,  and  of  other  German 
scientific  investigators,  were  very  damag- 
ing to  the  claims  of  carbolic  acid  as  a 
germicide,  and  as  a  coagulator  of  albu- 
men. In  his  treatise  "Ueber  Desinfec- 
tion,"  Dr.  Koch  deduced  from  his  careful 
and  laborious  experiments  minutely  de- 
scribed, that  the  value  of  carbolic  acid 
was  greatly  limited  as  a  germicide,  and 
that  for  the  destruction  of  spores  it  was 
altogether  useless,  being  almost  without 
action  ;  but  that  it  could  be  used  to  de- 
stroy micro-organisms  free  from  spores. 
This  was  when  used  in  a  watery  solution ; 
still  stronger  was  his  opinion  as  to  an 
oily  solution.  He  stated  that  in  solutions 
of  oil  or  alcohol,  carbolic  acid  did  not  ex- 
hibit the  slightest  antiseptic  action.  To 
this,  the  remarks  of  Dr.  Sansom  had  al- 


199 

ready  pointed.  It  must  be  remembered 
that  it  was  in  an  oily  solution,  i.e.,  dis- 
solved in  the  tar  oils,  that  carbolic  acid 
was  applied  to  timber.  G.  "Wolff  hugel 
and  G.  v.  Knorre  followed  up  Koch's  in- 
vestigations, and  spoke  of  the  inactivity 
of  an  oily  solution  of  carbolic  acid ;  of  its 
inferior  powers  of  penetration  into  porous 
solids,  and  of  its  inferiority  in  the  de- 
struction of  fungi.  F.  Boillat,  who  fol- 
lowed up  the  experiments  of  Koch  in  the 
laboratory  of  Professor  Nencki  at  Bern, 
found  that  albumen,  when  completely  co- 
agulated with  an  excess  of  carbolic  acid, 
formed  no  permanent  combination  there- 
with. He  was  able  to  wash  out  on  a  fil- 
ter the  whole  of  the  carbolic  acid  from 
the  albumen  precipitate,  after  which, 
upon  exposing  it  to  the  atmosphere  dur- 
ing forty-eight  hours,  the  albumen  be- 
came putrid.  Mr.  Carruthers  had  spoken 
of  the  presence  of  free  crystallized  car- 
bolic acid  in  the  cells  of  a  small  piece  of 
a  wooden  hurdle.  But  carbolic  acid 
would  not  crystallize  out  of  the  oils  hold- 
ing it  in  solution ;  it  could  only  be  ob- 


200 

tained  in  that  state  of  purity  by  a  long 
and  complicated  chemical  process,  and 
the  crystals  would  immediately  liquefy 
when  exposed  to  the  atmosphere.  The 
minute  particles  seen  by  Mr.  Carruthers 
were  probably  naphthaline,  or  one  of  the 
other  semi-solids  of  the  higher  distillates 
of  coal-tar.  The  condition  of  this  hurdle 
corresponded  exactly  with  that  of  enor- 
mous masses  of  successfully  creosoted 
timber  as  typified  by  the  samples  exposed 
during  this  discussion,  and  the  author 
thought  that  the  final  question  of  Mr. 
Carruthers  had  been  fully  answered  by 
many  authorities  quoted  in  the  paper. 

In  reply  to  Mr.  C.  de  Laune,  the  au- 
thor would  remark  that  his  paper  had  a 
much  wider  object  in  view  than  the  mere 
question  of  carbolic  acid;  the  presence 
or  absence  of  that  body  would  not  explain 
Mr.  de  Laune's  difficulty.  No  honest 
creosote  made  from  coal-tar,  whether 
"  London"  or  "country"  oil,  whether 
with  much  or  little  tar  acid,  contained 
any  ingredient  which  could  injure  timber ; 
the  only  question  was,  which  of  those  in- 


201 

gradients  was  most  efficacious  and  most 
durable.  The  question  as  to  which  was 
the  easiest  to  put  into  the  timber  was  of 
much  less  importance.  Some  small  pieces 
of  hurdles,  &c.,  had  been  shown  during 
the  discussion,  and  alluded  to  by  Dr. 
Voelcker,  Mr.  Carruthers,  and  Mr.  de 
Xiaune ;  Mr.  E.  A.  Cowper  had  detected 
the  reason  why  one  had  succeeded  and 
the  other  failed.  The  first  had  had  plen- 
ty of  creosote  put  into  it ;  the  others  but 
very  little.  Mr.  de  Laune  had  made  a 
detailed  statement  to  the  author,  which 
was  briefly  as  followed:  That  he  had 
been  in  the  habit  of  preparing  different 
kinds  of  timber  of  various  densities,  and 
frequently  in  a  wet  or  unseasoned  state 
by  boiling  the  wood  in  creosote  in  open 
tanks  and  without  a  thermometer;  and 
that  he  did  not  keep  the  timber  in  the 
tanks  more  than  twelve  hours,  as  a  long- 
er operation  rendered  it  brittle — a  very 
significant  fact.  He  said  that  he  had  not 
latterly  superintended  these  operations 
personally,  and  that  he  did  not  regard 
the  process  as  a  scientific  one,  but  thought 


202 

that  it  could  be  carried  out  by  odd  hands, 
old  men,  or  boys.  A  good  many  years 
ago,  the  author  had  had  considerable  ex- 
perience in  preparing  timber  in  open 
tanks  with  corrosive  sublimate,  sulphate 
of  copper,  and  also  with  creosote.  The 
time  for  leaving  the  timber  in  the  tank, 
to  be  injected  by  the  metallic  salts  in 
watery  solution,  which  penetrated  more 
readily  than  creosote,  was  generally  cal- 
culated at  about  twenty-four  hours  1'or 
every  inch  in  thickness  of  the  wood. 
With  the  creosoting  process  it  was  essen- 
tial that  the  water  in  the  timber  should 
be  first  got  rid  of ;  the  presence  of  the 
water  prevented  the  entrance  6f  the  cre- 
osote oils.  Even  with  the  cylinder-proc- 
ess, where  the  oil  was  driven  in  under 
pressure,  engineers  insisted  upon  the 
timber  being  dry,  and  they  weighed  it- 
before  and  after  the  operation,  to  check 
the  quantity  of  creosote  injected.  "With 
the  open- tank  system  more  care,  and  not 
less  care,  was  necessary  than  with  the 
superior  apparatus.  But  soft  young 
timber,  if  properly  seasoned  and  then 


203 

subjected  to  creosote  at  a  moderate  heat, 
could  without  difficulty  be  made  to  im- 
bibe a  sufficient  quantity  of  creosote  of 
any  kind  manufactured  in  this  country. 
But  if  the  timber  was  wet,  it  was  not 
amenable  to  treatment  by  creosote  in 
open  tanks  at  a  moderate  temperature, 
and  if  the  creosote  was  raised  to  a  tem- 
perature even  approaching  to  its  boiling- 
point,  which  was  about  400°  Fahrenheit, 
it  would  cause  the  timber  immersed  in  it 
to  become  as  brittle  as  a  carrot.  Timber 
should  not,  under  any  circumstances,  be 
subjected  to  a  higher  temperature  than 
250°  Fahrenheit.  It  would,  therefore,  ap- 
pear that  Mr.  de  Laune's  difficulties  were 
to  be  explained  by  his  methods  of  oper- 
ation. He  had  told  the  author  that  he 
had  for  many  years  procured  all  his  creo- 
sote from  the  same  works,  a  small  local 
manufactory,  where  the  tars  of  the  dis- 
trict were  distilled.  It  had  been  ascer- 
tained that  the  creosotes  manufactured  at 
the  works  in  question  had  not  essentially 
varied  in  type,  whilst  even  as  regarded 
carbolic  acid,  if  the  analysis  quoted  by 


204 

Mr.  de  Laune  was  correct,  the  quantity 
contained  in  the  sample  was  considerably 
above  the  average,  although  this  was  a 
point  to  which  the  author  attributed  but 
little  importance.  He  was  surprised  to 
find,  in  the  report  accompanying  the  an- 
alysis alluded  to,  a  statement  to  the  ef- 
fect that  "good  creosote  should  yield 
quite  75  per  cent,  of  volatile  oils  (sic) 
containing  10  to  15  per  cent,  of  crude 
carbolic  acid."  No  creosotes  used  for 
timber-preserving,  under  any  specifica- 
tion, had  ever  been  required  to  contain 
more  than  from  2^  to  5  per  cent,  of  crude 
carbolic  acid.  The  recommendation  of 
"  volatile  oils  "  was  a  mistake  which  was 
obvious  to  all  experts ;  but  it  might  have  a 
bad  effect  in  encouraging  the  use  of  some  of 
the  worst  adulterants,  substances  sold  as 
creosote  which  were  not  derived  from  coal 
tar  at  all.  The  report,  although  issued 
from  the  laboratory  of  the  Royal  Agricul- 
tural Society,  was  signed  for,  but  not 
by,  Dr.  Voelcker.  The  author  had  un- 
derstood that  Dr.  Voelcker  was  at  the 
time  absent  owing  to  illness ;  he  would 


205 

not  therefore  have  alluded  to  it  but  for 
the  fact  that  this  report  had  been  brought 
so  prominently  into  notice  by  Mr.  de 
Laune,  and  that  extracts  from  it  had 
been  published  in  an  agricultural  journal. 

The  author  had  used  creosoting  for 
farm  purposes,  for  fences,  hurdles,  and 
for  many  years  also,  for  piles  and  fences 
for  his  wharves.  He  always  used  for  him- 
self the  type  of  creosote  he  recommended 
to  others,  and  it  had  proved  invariably 
successful  in  his  own  case. 

The  author  was  asked  by  Mr.  Clemin- 
son  why  he  had  not  alluded  to  the  proc- 
ess of  Mr.  Blythe.  If  by  Blythe's  process 
was  meant  the  attempt  to  introduce  the 
creosote  oils,  or  any  part  of  them  into 
timber  in  the  form  of  vapor,  the  subject 
had  been  fully  treated  in  the  paper.  For 
the  operations  described  as  having  been 
carried  out  for  the  Compagnie  des  Che- 
mins  cle  Fer  de  1' Quest,  the  apparatus 
u'sed  was  supplied  by  Mr.  Blythe.  The 
experiments  of  Mr.  Seidl  were  described 
by  him  as  having  been  carried  out  by 
"Blythe's  process."  Engineers  in  Eng- 


206 

land  had  recently  had  an  opportunity  of 
witnessing  similar  experiments  at  the 
•works  of  Messrs.  Connor,  at  Millwall. 
After  the  dismantling  of  these  works,  the 
author  had  purchased  the  greater  part  of 
the  machinery  for  the  purpose  of  adapt- 
ing it  to  his  own  processes,  so  that  he 
had  again  had  an  opportunity  of  studying 
the  question.  By  slow  evaporation,  fluids 
gradually  volatilized  at  temperatures  much 
below  their  boiling-points.  But  pressure 
from  their  vapors  could  only  be  obtained 
at  temperatures  exceeding  their  boiling- 
points.  Thus  water  gradually  evaporated 
even  from  a  frozen  surface,  but  no  tension 
of  its  vapor  could  be  produced  except  at 
a  temperature  exceeding  its  boiling-point, 
212°  Fahrenheit.  The  boiling  point  of 
the  creosote  oils  ranged  from  about  400° 
to  760°  Fahrenheit,  that  of  carbolic  acid 
when  separated  from  these  oils  being  360° 
Fahrenheit,  and  of  cresylic  acid  390° 
Fahrenheit.  Now,  it  was  well  known 
that  timber  for  the  purposes  of  the  en- 
gineer was  injured  and  rendered  brittle 
and  unsafe  at  a  temperature  much  ex- 


207 

s 

ceeding  250°  Fahrenheit.  How  then 
could  those  tar  products  be  introduced 
under  pressure  into  the  timber  as  vapor, 
whether  accompanied  or  not  by  super- 
heated steam,  without  injuring  the  tim- 
ber? Either  the  temperature  must  be 
raised  above  danger  point  for  the  wood, 
or  nothing  but  the  vapor  of  water  would 
be  driven  into  it.  This  applied  to  the  first 
part  of  the  process.  Of  course,  if  it  was 
followed  up  by  an  injection  of  the  creo- 
sote oils  in  the  usual  manner,  this  second 
part  of  the  process  covered  the  deficien- 
cies of  the  first  operation.  The  presence 
of  any  of  the  components  of  the  tar-oils 
could  be  detected  in  the  timber  by  chem- 
ical tests.  When  specimens  of  wood  had 
been  produced,  which  had  been  prepared 
by  the  injection  of  tar-oil  vapors  in  suffi- 
cient quantity  to  have  a  practical  value  in 
the  preservation  of  timber,  and  at  a  tem- 
perature not  exceeding  250°  Fahrenheit, 
the  author  would  be  very  glad  again  to 
give  his  best  attention  to  this  part  of  the 
subject. 

He  was  glad  to  be  able  to  reply  to  the 


208 

question  of  Mr.  Lawford,  with  regard  to 
the  Midland  Railway  Company.  In  1866, 
at  a  meeting  of  the  Institution,  Mr.  Cross- 
ley,  the  engineer  of  that  company  an- 
nounced that,  although  he  admitted  that 
creosoting  stopped  decay,  he  had  given 
up  that  process  from  a  calculation  of 
economy  based  on  the  assumption,  that 
with  very  heavy  traffic  like  that  which 
prevailed  over  the  lines  of  his  company, 
the  sleepers  were  worn  out  by  hard  work 
before  they  had  time  to  decay.  The  au- 
thor would  suggest  that  incipient  decay 
of  unprepared  sleepers  often  set  in  at  a 
very  early  period  of  their  service,  especi- 
ally through  cracks  and  bolt-holes ;  the 
fastenings  of  the  chairs  thereupon  became 
loosened,  and  the  mechanical  destruction 
of  the  sleepers  hastened.  But  Mr.  Law- 
ford  would  be  glad  to  hear  that  the  Mid- 
land Railway  Company  had  again  adopted 
creosoting  ;  they  had  had  large  quantities 
of  sleeper  creosoted  during  the  last  few 
years. 

In   reply   to  Mr.  Roberts,  the  author 
had  never  found  any  difficulty  in   com- 


209 

pletely  saturating  the  sap-wood  with  the 
London  oils  where  the  timber  had  been 
sufficiently  dry.  Mr.  Coisne's  experience 
with  shavings  were  for  the  purpose  of  as- 
certaining what  kind  of  creosote  lasted 
best,  and  he  effected  a  complete  satura- 
tion both  with  the  thin  oils  and  with 
thick  oils.  The  thinnest  oils  did  not  pre- 
serve the  woody  fiber  from  rotting,  even 
with  so  good  an  injection,  whilst  the 
heavier  oils  did.  A  fortiori,  the  thinner 
oils  would  be,  by  themselves,  still  more 
unreliable  with  the  inferior  injection  car- 
ried out  in  practical  operations  with  tim- 
ber. It  must  also  be  borne  in  mind  that 
Mr.  Coisne  did  not  stop  at  these  experi- 
ments, but  had  confirmed  them  by  twenty 
years'  subsequent  treatment  of  timber  on 
a  very  large  scale,  for  the  Belgian  State 
Railways.  The  chapter  in  Mr.  Coisne's 
1871  pamphlet,  upon  the  choice  of  creo- 
sote oils  was  a  most  interesting  and  prac- 
tical one. 

With  reference  to  the  author's  process 
for  removing  water  from  the  timber  at 
the  time  of  creosoting,  the  following  ex- 


210 

perinaent   had   been   carried   out   at   his 
works  since  the  paper  had  been  read. 

Six  square  fir-sleeper  blocks,  each  8 
feet  11  inches  by  10  inches  by  10  inches, 
saturated  with  moisture,  were  cut  into  10 
inches  by  5  inches  sleepers.  One  sleeper, 

A,  from  each  block  was  prepared  by  the 
new  method,  the  corresponding  sleeper, 

B,  from  the  same  block,  by  the  old  meth- 
od, so  that  in  each  instance  the  results 
with   the   two   halves   of   the   same   log 
could  be  contrasted.     Care  was  taken  to 
choose  -blocks   having  the  heart  in  the 
center,  and  with  the  texture  of  the  two 
halves  as  nearly  as  possible  similar. 

From  the  six  sleepers,  A,  water  was 
withdrawn  by  the  new  process  to  the  ex- 
tent, ascertained  by  weighing  the  water, 
of  120  Ibs. ;  yet  the  sleepers,  when  with- 
drawn from  the  cylinder  after  the  process 
was  completed,  weighed  155  Ibs.  more 
than  when  put  in,  thus  showing  that  they 
had  absorbed  275  Ibs.  of  creosote.  As 
their  total  cubic  contents  were  18.57 
cubic  feet,  their  average  loss  of  water 
was  6.45  Ibs.  per  cubic  foot ;  their  aver- 


211 

age  gain  of  creosote  was  14.8  Ibs.  per 
cubic  foot. 

The  six  sleepers,  B,  were  creosoted  by 
the  ordinary  process.  Being,  like  the 
others,  very  wet,  and  having  no  moisture 
extracted  from  them,  the  results  of  their 
being  weighed  before  and  after  creosot- 
ing  showed  an  absorption  of  116  Ibs.  of 
creosote  only,  or  an  average  of  6.29  lbs» 
per  cubic  foot.  The  separate  absorp- 
tions of  these  six  sleepers  were  as  fol- 
lowed :  9.04  Ibs.,  4.52  Ibs.,  2.9  Ibs.,  6.13 
Ibs.,  9.36  Ibs.,  and  5.49  Ibs.  per  cubic 
foot  respectively,  thus  illustrating  the 
uncertain  results  of  creosoting  timber 
when  too  wet  by  the  ordinary  method. 
They  were  placed  in  the  cylinder  with  a 
charge  of  ordinary  dry  sleepers,  which 
took  up  on  the  average  rather  more  than 
10  Ibs.  of  creosote  per  cubic  foot. 

The  result  with  sleepers  A  was  inter- 
esting, as  it  showed  that  by  the  new 
process  wet  timber  could  have  its  mois- 
ture at  once  removed,  and  a  large  quan- 
tity of  creosote  injected  without  difficulty. 
All  twelve  sleepers,  both  A  and  B,  were 


212 

afterwards  cross-cut  at  6  inches,  9  inches, 
12  inches,  and  at  4  feet  6  inches  from 
their  ends,  the  corresponding  section  of 
A  and  B  being  constrasted  and  photo- 
graphed. The  sleepers  A  were  found  not 
only  to  have  absorbed  a  large  quantity  of 
creosote,  but  the  creosote  was  much  more 
evenly  distributed  than  was  the  case  with 
sleepers  B. 

Might  the  author  be  permitted  to  sum 
up  the  evidence  which  had  been  produced 
during  the  discussion  as  to  the  best  class 
of  antiseptics  for  timber?  Both  engi- 
neers and  chemists  would  probably  agree 
with  him  that  after  forty-five  years'  dis- 
cussion of  this  engineering  problem  the 
time  had  gone  by  for  dogmatic  assertion, 
unsupported  either  by  experiment  in  the 
laboratory  or  by  recorded  experience  in 
engineering  works.  In  the  paper  he 
had  called  the  germ  theory  a  severe 
but  salutary  test  for  these  antiseptics. 
As  a  matter  of  fact,  the  subject  had 
received  valuable  elucidation  from  the 
labors  and  discoveries  of  a  number  of 
eminent  men,  who  had  studied  the  physi- 


213 

ology  of  the  bacteria.  In  the  application 
of  the  remedies,  however,  the  operations 
of  the  timber-preserver  diverged  from 
those  of  the  physician  to  the  human  body. 
In  combating  those  terrible  enemies  the 
bacteria,  which  were  pathogenic  to  ani- 
mal life,  the  great  difficulty  was  that 
many  of  the  remedies  effectual  against 
the  bacteria  intefered  with  the  vital  func- 
tions of  the  patient.  On  the  other  hand, 
the  physician  could  repeat  remedies  when- 
ever the  malignant  symptons  reappeared. 
Therefore  antiseptics,  more  or  less  vola- 
tile, were  sometimes  more  useful  to  the 
physician  than  others  of  a  more  perma- 
nent character,  because  they  did  not  accu- 
mulate in  the  system  of  the  patient.  In 
preserving  timber,  the  problem  differed 
materially.  The  vital  functions  of  the 
plant  had  ceased ;  stronger  poisons,  and 
substances  which  clogged  up  the  cells  and 
tissues,  could  be  employed,  provided  al- 
ways that  they  were  of  such  a  nature  as 
not  to  injure  the  structure  of  the  wood. 
But  the  remedy  must  be  applied  once  for 
all.  In  the  majority  of  cases  where  tim- 


214 

ber  was  once  placed  in  engineering  works 
the  supply  of  the  antiseptic  could  not  be 
renewed.  Therefore  the  very  first  condi- 
tion was  that  the  antiseptic  should  be  of 
a  permanent  constitution.  Let  this  rule 
be  applied  to  the  evidence  offered  during 
the  discussion.  Antiseptics  for  timber 
had  been  described:  1st,  as  coagulators 
of  albumen  ;  2d,  as  germicides ;  3d,  as 
sterilizers,  rendering  the  cells  of  the  wood 
unfit  for  the  development  of  fungi  or 
bacteria ;  4th,  as  germ-excluders,  closing 
the  entrances  against  the  intrusions  of 
the  enemy. 

Was  not  too  much  value  still  attached 
by  some  to  the  coagulation  of  the  albu- 
men in  wood  ?  Albumen  formed  an  ex- 
tremely small  portion  of  the  wood ;  in  fir 
it  varied  from  0.5  to  0.9  per  cent.  Those 
parts  of  timber  containing  the  smallest 
portions  of  albumen  were  nevertheless 
liable  to  decay ;  the  mere  coagulation  of 
the  albumen  did  not  protect  the  bulk  of 
the  timber  from  destruction.  Did  coagu- 
lation preserve  even  the  albumen  itself 
from  destruction?  Sansom,  Angus  Smith, 


215 

and  other  authorities  found  that  it  did 
not.  The  author  took  a  hard-boiled  egg, 
a  very  complete  specimen  of  coagulated 
albumen,  removed  the  shell,  and  exposed 
it  to  the  sea  breezes  on  a  high  point  of 
the  Atlantic  shore  of  the  island  of  Mull. 
In  a  few  days  signs  of  putrefaction  were 
visible;  in  eight  days  the  albumen  was 
coated  with  various  species  of  micrococ- 
cus,  cromogenes  and  other  agents  of  de- 
struction. The  egg  had  become  a  mass 
of  corruption.  Coagulation  had  not  pro- 
tected albumen  from  putrefaction.  What 
was  the  result  when  coagulation  was  pro- 
duced, not  by  heat,  but  by  the  action  of 
an  antiseptic  body1?  Did  not  the  result 
depend  mainly,  if  not  altogether,  upon 
the  germicide  properties  of  the  antiseptic, 
and  upon  its  abiding  presence  ?  Or,  thus 
produced,  did  coagulation  per  se  effect  a 
new  combination  with  permanent  results  I 
In  the  case  of  carbolic  acid,  a  host  of  in- 
vestigators said,  No.  Their  experiments 
appeared  to  prove  that  carbolic  acid  was 
volatile  in  the  air,  soluble  in  the  water, 
and  that  its  compounds  were  not  stable. 


216 

Boillat,  in  his  experiments,  realized  the 
extreme  conditions  desired  by  those  the- 
orists who  thought  that  carbolic  acid  had 
a  permanent  effect  upon  timber  ;  he  pro- 
duced a  perfect  coagulation  of  albumen 
with  an  excess  of  carbolic  acid.  Yet  a 
mere  washing  with  water  removed  the 
whole  of  the  carbolic  acid,  and  the  albu- 
men putrefied  on  exposure  to  the  air. 
Carbolic  acid,  therefore,  would  appear  to 
have  had  no  permanent  effect  upon  albu- 
men. The  author  agreed  with  Dr.  Ber- 
nays  that  if  coagulation  by  carbolic  acid 
were  desirable,  2  per  cent,  of  that  body 
might  be  retained ;  but  having  in  view 
the  foregoing  evidence,  what  was  the 
value  of  the  coagulation  theory  at  all  as 
applied  to  timber-preserving  ?  There  had 
been  some  idea  that  carbolic  acid  lin- 
gered in  the  timber  in  some  unrecognized 
form.  The  author  had  had  occasion  to 
test  sleepers  a  few  weeks  after  creosoting  ; 
if  this  were  done  before  the  carbolic  acid 
had  time  to  evaporate,  it  could  be  found 
in  the  wood  by  the  ordinary  tests,  and  a 
quantitative  analysis  made.  On  the  other 


217 

hand,  Dr.  Tidy,  who  was  not  unwilling  to 
find  it  in  combination,  had  searched  for  it 
after  twelve  months,  and  had  not  found  it 
by  the  ordinary  tests,  that  is,  in  sufficient 
quantity  to  have  any  practical  result.  But 
whenever  it  was  present  there  were  tests 
subtle  enough  to  detect  it,  even  in  such 
infinitesimal  quantities  as  to  have  no 
practical  value,  as  was  evidenced  by  the 
experiments  of  Mr.  Greville  Williams. 
Notwithstanding  theories  and  experi- 
ments, did  carbolic  acid,  when  put  into 
timber,  do  any  good  there  ?  Mr.  Coisne, 
Mr.  Greville  Williams,  and  the  author, 
not  only  never  found  it  to  have  contrib- 
uted to  the  success  of  old  creosoted  tim- 
ber, but  Mr.  Coisne's  experiments  went 
further  still.  He  injected  woody  fiber 
with  light  oils  and  an  excess  of  tar  acids, 
and  the  woods  rotted,  whilst  the  woods 
creosoted  with  heavy  oils,  and  without 
any  tar  acids,  were  preserved. 

There  was  one  point  respecting  which 
there  had  been  a  consensus  of  opinion  on 
the  part  of  all  who  had  taken  part  in  the 
discussion,  namely,  that  for  the  prepara- 


218 

tion  of  timber,  creosoting  had  been  un- 
deniably more  successful  than  corrosive 
sublimate,  sulphate  of  copper,  or  chlor- 
ide of  zinc.  Could  this  be  at  all  due  to 
carbolic  acid?  How  was  this  possible, 
when  a  host  of  authorities  proved  that 
carbolic  acid  was  less  permanent  in  its 
effects  than  the  three  metallic  salts  al- 
luded to,  and  very  considerably  less  pow- 
erful as  a  germicide  than  corrosive  sub- 
limate or  sulphate  of  copper.  In  a  valu- 
able work  upon  bacteria  by  Magnin  and 
Sternberg  there  was  a  long  list  of  anti- 
septics, with  a  statement  as  to  their  com- 
parative potency  as  germicides,  compiled 
from  the  latest  authorities.  Carbolic 
acid. was  low  in  the  scale.  Dr.  Sternberg 
gave  the  strength  of  solutions  of  differ- 
ent kinds  which  had  been  found  efficacious 
in  preventing  the  development  of  the 
septic  micrococcus,  the  following  amongst 
many  others  : 

Corrosive  sublimate. .  .1  part  in  40,000 
Sulphate  of  copper. ..  .1       "  400 

Chloride  of  zinc 1       "  200 

Carbolic  acid 1      "  200 


219 

These  were  in  watery  solution.  To  this 
must  be  added  the  statements  that  in  oily 
solution  the  antiseptic  power  of  carbolic 
acid  was  diminished,  according  to  San- 
som  and  Angus  Smith ;  altogether  it  was 
nil  according  to  Koch.  It  was  evident 
that  there  was  a  vast  accumulation  of  sci- 
entific evidence  in  confirmation  of  the 
continually  reiterated  statements  of  those 
practical  men,  who  had  had  the  largest 
and  longest  experience  in  preparing  tim- 
ber, to  the  effect  that  it  was  not  to  car- 
bolic acid,  but  to  other  substances  con- 
tained in  the  tar  oils,  that  the  superiority 
of  the  creosoting  process  over  the  other 
three  methods  was  due.  Mr.  Lowe  was 
well  known  as  one  of  the  highest  scien- 
tific and  practical  authorities  upon  the 
tar  acids,  and  he  had  given  much  valu- 
able information  in  his  communication  to 
the  Institution.  On  the  other  side,  the 
absence  of  evidence  was  even  more  re- 
markable than  many  of  those  interested 
in  this  subject  would  perhaps  have  an- 
ticipated. No  chemist  had  brought  for- 
ward even  a  laboratory  experiment  in 


220 

proof  of  any  permanent  effect  of  carbolic 
acid  upon  albumen.  No  practical  man 
had  produced  a  proof  that  that  substance 
had  had  any  lasting  effect  upon  timber. 
The  author  submitted  that  the  claims  of 
carbolic  acid  as  an  antiseptic  for  timber 
had  not  been  proven. 

What,  then,  were  the  substances  in  the 
creosote  oils  which  had  insured  the  supe- 
riority of  that  process  over  the  others? 
If  the  author  were  asked  the  question, 
he  would  remark  that  the  object  being 
the  prolonged  preservation  of  timber, 
antiseptics  should  be  chosen  which  re- 
mained longest  in  the  timber.  That  the 
different  constituents  of  the  creosote  oils, 
showed  a  gradation  from  the  lightest  and 
most  volatile  bodies  at  the  carbolic,  or 
left-hand  end  of  the  scale,  up  to  the  least 
volatile  and  most  permanent  bodies  at 
the  right-hand  end.  Divide  the  bulk  of 
the  oils  roughly  in  half.  Would  the  con- 
stituents of  the  right-hand  half  of  them- 
selves insure  the  preservation  of  the  tim- 
ber? Yes,  excellently  well.  They  con- 
tained germicides  and  solidifying  mate- 


221 

rials ;  they  were  both  sterilizers  and 
germ-excluders  ;  they  would  not  evapo- 
rate, except  at  an  enormously  high  tem- 
perature. Nevertheless  in  their  united 
bulk  they  were  perfectly  fluid  at  a  tem- 
perature of  100°  Fahrenheit ;  they  were 
insoluble  in  water ;  they  could  be  injected 
into  timber,  in  quantity  exceeding  the 
maximum  which  any  engineer  had  as  yet 
required.  Would  the  other,  or  left-hand 
part  of  the  group,  taken  by  themselves, 
preserve  timber?  Much  less  perfectly, 
as  they  were  more  volatile.  "Would  a  still 
further  fractioning  to  the  left,  if  it  were 
practicable,  insure  a  better  result  ?  Not 
so,  but  a  worse  one  still ;  for  the  lightest 
oils,  which  contained  the  greatest  portion 
of  the  tar  acids,  were,  like  the  tar  acids 
themselves,  the  most  volatile  portions  of 
all. 

The  author  trusted  that  he  had  made 
clear  his  reasons  for  specially  objecting 
to  large  percentages  of  tar  acids.  Take 
an  honest  heavy  cresote,  free  from  adul- 
teration, free  from  mutilation,  containing, 
say,  5  per  cent,  of  tar  acids.  If  this 


222 

sample  were  refused  because  it  did  not 
contain  8  or  10  per  cent.,  the  tar-distiller 
was  induced  to  remove  a  large  portion  of 
the  heavier  constituents  of  the  bodies  to 
the  right  hand  of  the  scale,  in  order  to 
make  the  proportion  of  tar  acids  larger 
in  the  portion  remaining.  He  believed 
that  those  heavier  portions  were  the  best. 
He  thought  that,  provided  the  oils  were 
sufficiently  fluid  at  the  temperature  at 
which  they  were  injected,  there  should  be 
no  restriction  as  to  maximum  specific 
gravity  or  maximum  boiling-point.  If 
larger  and  stronger  doses  of  germicides 
were  desired,  it  would  be  far  better  to 
put  them  into  the  wood  in  the  shape  of 
corrosive  sublimate  or  sulphate  of  copper, 
in  addition  to  the  heavy  oils.  This  could 
be  done  by  a  double  process  of  prepara- 
tion, with  respect  to  which  he  had  been 
lately  experimenting. 

Timber  preserved  by  antiseptic  treat- 
ment was  an  engineering  material  com- 
peting with  other  materials,  both  as  to 
price  and  durability.  Members  of  the 
Institution  would  appreciate  the  endeav- 


223 

ors  of  the  author  to  emancipate  an  im- 
portant industry  from  the  effects  of  any 
theories  which,  themselves  unproven, 
might  stand  in  the  way  of  improvement, 
either  as  to  diminished  cost  or  increased 
efficiency. 


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VAN  NOSTR«_SCIE»CE  SERIES, 

No.  28.— ON  TRANSMISSION  OF  POWER- BY 
WIRE  ROPE.  By  ALBERT  W.STAHI, 
Fully  illustrated. 

No.  29.— INJECTORS  ;   THEIR   THEORY  AND 
USE.     Translated  from  the   French  of 
I  M.  LEON  POTCHET.     Illustrated. 

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THE  MAGNETISM  OF  IRON  SHIPS. 

*  By  PROF.  FAIRMAN  ROGERS.  Illustrated. 

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AND  COUNTRY.  By  GEORGE  E. 
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Sanitary  and  Agricultural  Works. 

No  32. -CABLE  MAKING  FOR  SUSPENSION 
BRIDGES,  as  exemplified  in  the  Con- 
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WlLHELM   HlLDENBRAND,  C.  E.       Fully 

illustrated. 
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ARD,    C.  E.         Translated    from     thf 
French,  by  L.  F.  VERNON  HARCOURT, 
M.  I.  C.  E. 

No.  35.— THE  ANEROID  BAROMETER  :  Its  Con- 

struction  and  Use.     Compiled  by  Prof.  G. 

W-  PLYMPTON.  3d  Revised  Edition.  Illus. 

No.  36.— MATTER  AND  MOTION.     By  J.  CLERK 

MAXWELL. 

No.  37.— GEOGRAPHICAL  SURVEYING  :  Its 
Uses,  Methods  and  Results.  By  FRANK 
DE  YEAT  x  CARPENTER. 

No.  88.— MAXIMUM  STRESSES  IN  FRAMED 
BRIDGES.  By  Prof.  WM.  CAIN.  Illus- 
trated. 

No.  39  -A  HAND-BOOK  OF  THE  ELECTRO- 
MAGNETIC TELEGRAPH.  By  A.  E. 
LORING,  a  Practical  Telegrapher.  Illus- 
trated. 


